- Montreal 2019
- Fredericton 2018
- Vancouver 2017
- London 2016
- Regina 2015
- Halifax 2014
- General / Générale
- CSCE 2014 General Conference / Congrès général 2014 de la SCGC
- 13th International Environmental Specialty Conference / 13ème Conférence Internationale spécialisée sur l'environment
- 4th International Structural Specialty Conference / 4ème Conférence Internationale spécialisée sur les structures
- 10th International Transportation Specialty Conference / 10ème Conférence Internationale spécialisée sur les transports
- Montreal 2013
- General / Générale
- Congrès général 2013 de la SCGC / CSCE 2013 General Conference
- 4th Specialty Conference on Coastal, Estuary and Offshore Engineering / 4ème Ingénierie côtière et en milieu maritime
- 3rd Specialty Conference on Material Engineering & Applied Mechanics / 3e Conférence spécialisée sur le génie des matériaux et mecanique appliquée
- 4th Construction Specialty Conference / 4e Conférence spécialisée sur la construction
- 3rd Specialty Conference on Disaster Prevention and Mitigation / 3e Conférence spécialisée sur la prevention et la mitigation des désastres naturels
- The 2nd Forum on Professional Practice and Career Development / 2e Forum sur la pratique professionnelle et le développement de carrière
- SMSB 2018
Papers - 2019 CSCE Annual Conference - Laval (Greater Montreal)
Advanced composite materials
Evaluating the Potential advantages of Basalt FRP when compared with Carbon FRP and conventional steel.
Yomna Hagras, Ramy Khalaf, Farid Mohamed, Ahmed Shehata, Amira Tobaa, Mariam Zaki, Reem Abou Ali, Mayer Farag, Athnasious Ghaly, Magdi Madi, Ezzeldin Yazeed Sayed-Ahmed, Mohamed N. Abou-Zeid
Ms. Yomna Hagras Mr. Ramy Khalaf Mr. Farid Mohamed Mr. Ahmed Shehata Ms. Amira Tobaa Ms. Mariam Zaki Ms. Reem Abou Ali Mr. Mayer Farag, The American University in Cairo Mr. Athnasious Ghaly, American University in Cairo Mr. Magdi Madi, The American University in Cairo Dr. Ezzeldin Yazeed Sayed-Ahmed, The American University in Cairo Dr. Mohamed N. Abou-Zeid, The American University in Cairo (Presenter)
The successful incorporation of steel as a reinforcement of concrete has been dominant over the past decades. However, steel corrosion represents a major threat in the construction industry. Therefore, the use of FRP composites as a reinforcement for concrete structures is in a continuous increase, due to their strengthening properties and significant resistance to corrosion. FRP systems exist as composites of a polymer matrix and a fibre. This fibre could be glass, aramid, carbon, or basalt. Numerous concerns exist regarding the use of glass, aramid, and carbon FRP with respect to the composite or its cost. The basalt FRP has been introduced but little research has been conducted to understand how it complements the advantages of an FRP system at a relatively low cost. Basalt is the most abundant volcanic igneous rock type in earth’s crust. Basaltic materials have a high performance in terms of strength, temperature range, resistance to acids, resistance to the alkalinity of concrete, and finally their lower cost grants them a high potential to replace carbon FRP and conventional steel. Continuous basalt fibres were first produced in 1984 and were found to require less energy than that required for glass or carbon fibres. Hence basalt fibres are environmentally safer than alternative FRP composites.
In this study attempts are taken to evaluate the performance of basalt FRP bars compared with carbon FRP bars and conventional steel bars. Fourteen specimens of RC are casted to fulfil this comparison. Eight are beams with common top reinforcement, stirrups spacing, and concrete properties. The difference is in bottom reinforcement where it was once steel, Carbon FRP, Basalt FRP, and a hybrid Basalt FRP and steel. These eight beams were tested for their behaviour under a flexure load through a four-point bending test. The six specimens were casted as columns with common stirrups spacing, and concrete properties. The behaviour of different reinforcements will be tested upon the application of an axial load. The bonding strength between concrete and different bars is tested through bond pull-out test. Furthermore, tests will be conducted on the thermal, chemical, and mechanical properties of individual bars.
This work is expected to yield a better understanding of the properties offered by FRP, assess the potential advantages and disadvantages, and determine its cost effectiveness in an attempt to reach an economic utilization of this fibre that can help designers in making more educated selections when used in concrete works.
Field Application of FRP Structural Strengthening Subjected to Excessive Heat and Fire
Bahira Abdulsalam, Ibrahim Mahfouz
Dr. Bahira Abdulsalam, CIISolutons Composite Infrastructure Innovation Solution Corp. Dr. Ibrahim Mahfouz , Banha University Egypt (Presenter)
In this paper Field application of structres strengthened using FRP systems and subject to heat and fire will be presented. The first case of the strengthening of a reinforced concrete bridge where the FRP layers will be subjected to excessive heat resulting from Environmental effects as well as high tempreature that can reach more than 120 degrees during the application of the asphalt layers. Which is in acsess to the glass transition tempreature of the FRP strengthening system. FRP laminated strips were installed on the top serface of the concrete brige were protected with a 70 mm thick heat protection layer possessing relatively high compressive strength capable of resisting the high intensity of the truck loads. Several heat protection materials where tested, and the one that was chosen was capable of fully protecting the FRP layers. The bridge has been sucsessfully used for a number of years. The paper will also present Field application of fully protecting a number of reinforced concrete columns againest fire. Where the strengthening demands of such columns where close to 100%. Extensive experimental studies were carried out in order to be able to choose the best material which is capable of fully protecting againest fire for a fire duration rating of a period of two hours. The results obtained for the fire protection layer used in this project was proven to be fully protecting the FRP strengthening layers for more than two hours.
FRP Materials for Rehabilitation of Buried Pipes
Anita Shiny Kanagaraj , Pedram Sadeghian
Ms. Anita Shiny Kanagaraj , Dalhousie University (Presenter) Dr. Pedram Sadeghian, Dalhousie University
Pipes are majorly used as culverts, storm water drains, sewers, oil and gas lines, and water conduits. Over time, these deteriorate and necessitate rehabilitation, in order to increase the service life of structure. Bonding a fiber-reinforced polymer (FRP) liner inside the pipe, is an effective rehabilitation technique to increase the strength and stiffness of deteriorated pipes. To do so, it is very important to know the structural behavior and mechanical properties of the FRP liner subjected to loading. This paper discusses the results of solid wall FRP liners with four layers of FRP, subjected to compressive transverse loading. A customized compression testing machine with string pots to measure the diametrical change and a load cell, was set up to test the liners under parallel-plate loading test method. Four specimens of glass FRP (GFRP) and two specimens of carbon FRP (CFRP) liners, having an average internal diameter of 333 mm were tested to find the diametrical change, stiffness factor (SF) and pipe stiffness (PS) at 5% and 10% diametrical change. Both GFRP and CFRP liners started cracking at springline. Also, the CFRP pipes lifted at the invert with crackling sound of the individual fibers breaking continuously until failure. GFRP liners reached an average peak load of 11.5 kN, whereas the CFRP liners reached 13.0 kN. An analytical model for diametrical deflection both in vertical and horizontal direction and their corresponding strains at spring line and crown/invert were developed to substantiate the geometrical non-linearity theoretically. The model is in good agreement with the experimental data, where the SF at 5% diametrical deflection matched with the model SF for GFRP and CFRP liners with an accuracy of 99.9% and 92.2%, respectively.
Interfacial Bond Strength between the Circular FRP Tube and Its Concrete Core
Ahmed Ali, Radhouane Masmoudi
Dr. Ahmed Ali, Sherbrooke University (Presenter) Mr. Radhouane Masmoudi, UniversitÃ© de Sherbrooke
The interfacial bond in concrete-filled fiber-reinforced polymer (FRP) tubes (CFFT) should be sufficient to provide full composite action between the FRP tube and its concrete core. Although, CFFT members had been investigated widely in the last two decades, there is no standards or guidelines to determine the interfacial bond strength on CFFT members. This study presents an experimental investigation of the interfacial bond strength between the concrete core and the fiber-reinforced polymer (FRP) tubes of circular pultruded concrete-filled FRP tubes (CFFTs). This research also provides a test method to determine the interfacial bond strength of the CFFT members. Six full-scale circular CFFT specimens were tested with two different tube sizes, 305 mm diameter and 406 mm diameter, 200 mm height, and all tubes have 12.7 mm tube wall thickness. All specimens were filled by the same concrete. The specimens were tested under a test setup prepared especially for these specimens. The specimens were loaded vertically, and the vertical load was applied on the concrete core while the specimen was supported vertically on the FRP tube only. The vertical loads and the slippage between the FRP tube and its concrete core were recorded to plot the interfacial bond-slip relationships for each specimen.
Severe Corrosion Behavior of Two-way Slabs under Different Accelerated Corrosion Techniques
Mahmoud Said, Amgad Hussein, Nick Gillis
Mr. Mahmoud Said, Memorial University of Newfoundland (Presenter) Dr. Amgad Hussein, Memorial University of Newfoundland Mr. Nick Gillis, SNC Lavalin Inc, Canada
The behaviour of severe corrosion was illustrated in this paper using two different accelerated techniques. Each accelerated technique reached the same corrosion level, 50% mass loss. One technique used constant voltage and the other one used constant current. Two full-scale two-way slabs of dimensions 1900 mm × 1900 mm × 150 mm were cast for this purpose. A column stub with a cross-sectional area of 250 mm × 250 mm and a height of 200 mm was attached to each slab. The quality of concrete was examined before inducing the corrosion by doing a rapid chloride penetration test to ensure an acceptable concrete quality against chloride ingress. The corrosion behaviour for each slab was assessed based on the results of the current, half-cell potential, corrosion cracks pattern, natural frequency, chloride content, and mass loss. Both techniques showed a close agreement between the actual and the theoretical mass loss, which was calculated using Faraday’s equation. It was observed that the corrosion cracks in constant voltage technique were induced randomly while in the other slab induced above the corroded bar. This could be attributed to the current value that was kept constant in constant current technique, while the current value varied in the constant voltage technique and reached high values. This could increase the probability of a constant voltage technique to cause more damage than a constant current.
AI and Automation
A machine-learning solution for quantifying the impact of climate change on roads
S. Madeh Piryonesi, Tamer El-Diraby
Mr. S. Madeh Piryonesi, University of Toronto (Presenter) Dr. Tamer El-Diraby, University of Toronto
Understanding the condition of roads is important to transportation departments. Therefore, modeling and predicting the deterioration of roads is crucial to road asset management. This paper provides a practical decision-support tool for predicting the condition of asphalt roads in the short term under a changing climate. Users have the option of running a predictive model under different values of climate stressors. The prediction of deterioration is done via machine learning. More than a thousand examples of road sections from the Long-Term Pavement Performance (LTPP) database were used in the process of model training. The results are implemented in a web-based platform, which includes a map with an interactive dashboard. Users can query any road, input its data, and get relevant predictions about its deterioration in two, three, five and six years. Since the attributes used for model training include important climatic features, such as temperature and precipitation, the users can run the model multiple times under different climate scenarios and get relevant analytics. This type of analysis is highly important knowing that climate change will be a significant factor in future infrastructure decision making. The results of this study could be useful to municipalities, policy-makers and transportation agencies who deal with large networks of assets under a varying climate.
Concrete Surface Defect Detection Using Deep Neural Network Based on LiDAR Scanning
Majid Nasrollahi, Neshat Bolourian, Amin Hammad
Mr. Majid Nasrollahi, Concordia University (Presenter) Ms. Neshat Bolourian, Concordia University Dr. Amin Hammad
Structural inspection of bridges is essential to improve the safety of the infrastructure systems. Visual inspection is the principal method of detecting surface defects of bridges. In order to automate the process of structural inspection, it is important to collect proper data sets and use an efficient approach to analyze them and find the defects. Light Detection and Ranging (LiDAR) scanners can collect high-quality 3D point cloud datasets. Furthermore, Deep Neural Networks (DNNs) have been recently used for detecting 3D objects within 3D point clouds. This paper aims to develop a method for detecting concrete surface defects using a DNN based on LiDAR scanning. Convolutional Neural Networks (CNNs) and Recurrent Neural Networks (RNNs) are two popular types of DNNs. PointNet is a CNN used extensively for analyzing 3D point sets. PointNet has three parts: classification, part segmentation, and semantic segmentation. The semantic segmentation part is originally designed to detect indoor building elements. In this paper, PointNet is adapted to detect surface defects using point cloud datasets from scanning bridge surfaces. The reason for selecting PointNet is that it is robust to missing and corrupted data.
Training and testing datasets are collected from concrete bridges and annotated manually. Five point cloud datasets are prepared in five areas, resulting in 3,572 annotated segments. These segments are classified into two classes, defect and non-defect. In order to use K-fold strategy for training and testing, about 20% of the segments are assigned as a testing dataset. Promising initial results have been obtained in spite of the small size of the training dataset. In order to increase the accuracy, our future work aims to prepare a bigger dataset to train the model.
INVESTIGATING THE USE OF VIRTUAL REALITY IN IMPROVING THE QUALITY OF DESIGN BIM FOR FACILITY MANAGEMENT
Devarsh Bhonde, Puyan A. Zadeh, Sheryl Staub-French
Mr. Devarsh Bhonde, The University of British Columbia Vancouver Dr. Puyan A. Zadeh, University of British Columbia Dr. Sheryl Staub-French, University of British Columbia (Presenter)
Building design is a complex and iterative process that requires collaboration between designers from numerous disciplines. Quality of design has a direct impact on project success especially during the operations and maintenance phase from an end-user perspective. Using modern approaches like Building Information Modelling (BIM) and Integrated Project Delivery (IPD) can help to mitigate design errors, omissions, and ambiguities. Nevertheless, there is potential to investigate how modern technologies can be used for improving the quality of design. This research aims to improve the quality of design by focusing on getting design inputs related to maintainability from relevant end-users. For this aim, the use of Virtual Reality (VR), with its potential for providing a stronger spatial understanding, is explored. A quasi-experimental approach is used to compare the performance of sixteen construction professionals who used traditional drawings and VR for providing design inputs. The participants completed pre-task and post-task questions to provide perceptions about their experience. The results suggest that participants found using VR easier and more accurate in comparison to traditional drawings. These findings are noteworthy because all the participants had substantial construction experience and used traditional drawings on a regular basis. The small sample size limits the generalizability of the results, but this study establishes as a proof of concept that VR is a viable option for getting design inputs from end-users to improve the quality of design.
Potential of Bayesian Networks for Forecasting the Ripple Effect of Progress Events
Kareem Mostafa, Tarek Hegazy
Mr. Kareem Mostafa, University of Waterloo (Presenter) Dr. Tarek Hegazy, University of Waterloo
As part of project control, project managers need to frequently update project progress and forecast project completion time. Current methods for status analysis and forecasting rely on developing performance indices such as the well-known Schedule Performance Index (SPI) and the Estimate at Completion (EAC) of the Earned-Value (EV) analysis. These indices, however, are developed with the assumption that the remaining part of the project will follow the same trend as the latest progress trend, without regard for how current events may shape future ones or how the experienced changes and interruptions may affect future ones (i.e., the ripple effect of progress events). As such, the general EV assumptions of continued progress trend might make the forecasting results misleading. While simulation and uncertainty analysis could improve forecasting, there is still a need for more accurate forecasting methods. This paper investigates the utilization of Bayes theorem of conditional probability and the benefits of developing Bayesian networks to predict project completion time based on a certain event(s) affecting the ongoing and/or the upcoming project tasks. The paper first presents an extensive literature review of existing applications of Bayesian Analysis in various domains. To facilitate accurate forecasting, a register of possible events that trigger changes in future forecasts is identified, and includes events such as productivity loss in similar tasks, payment delays, potential site congestion, etc. The paper then discusses the potential advantages as well as the challenges of developing Bayesian models. A hypothetical seven-activity schedule to is then presented to demonstrate the proposed concept and highlight the difference between schedule updates with and without Bayesian relationships among task durations. The flexibility and timeliness of Bayes Analysis could serve to quantify potential project delays which assists in decision-making regarding proactive remedial actions on construction projects.
SYSTEM DYNAMICS APPROACH TO ASSESS IMPACTS OF DISASTER RISKS ON INVESTMENT IN INFRASTRUCTURE
This paper presents a system dynamics approach to analyze funding allocation for long-term infrastructure growth, reinvestment in infrastructure for maintenance and upgrading and restoration of infrastructure damaged from disasters. The infrastructure comprises of individual infrastructure components, such as bridges, roads, water and sewer lines, oil and gas pipelines, and power lines. As a region or countryâ€™s security, well-being, and prosperity rely on the smooth, efficient and optimal functioning of the infrastructure components, continuous investment in infrastructure is critical. Investment in new infrastructure gets more attention compared to that in maintenance and upgrading of existing infrastructure. Reports on existing infrastructure in the United States and Canada show that there is substantial gap in investment on maintenance and upgrading of existing infrastructure. Moreover, risks such as disaster events frequently damage the infrastructure which may require to divert the scarce resources for the restoration of the damaged infrastructure. A system dynamics model is used to investigate sharing of resources between new and existing infrastructure under different investment scenarios. A sensitivity analysis is done to analyze the impact on available funding when disaster events impact the economy and damage the infrastructure. The results show that disasters cause further underinvestment in maintenance and upgrading of the infrastructure. This approach may be useful for all levels of governments to make informed decisions for optimal allocation of resources and for projecting long- term investment and growth scenarios.
The role and value of integrating AI, drones and associate technologies in construction projects
Azzeddine Oudjehane, Tareq Baker, Shahab Moeini
Dr. Azzeddine Oudjehane, SAIT Polytechnic (Presenter) Dr. Tareq Baker, SAIT Mr. Shahab Moeini, Southern Alberta Institute of Technology
The rationale to integrate and apply drone technology may differ pending on the industry sector, As a tool that improves communication, safety, and marketing, the use of drones in construction provides many advantages including increased productivity.
For decades, the construction industry has had the lowest productivity rate worldwide. Conservative and traditional managerial processes in the construction industry have impeded the adoption of innovative technologies such as unmanned systems, AI and big data.
In the past year alone, the construction sector has become the leading sector using drone technology. From site survey, safety induction, maintenance inspection, progress reporting, quality control, site logistics, virtual walkthrough marketing as well as legal dispute resolutions, Unmanned Systems have disrupted construction practices and processes. Hence, in 2018, a leading cloud software platform for drone operations measure a +239% year to year growth in construction applications. Unmanned Systems have also driven the application of associated technologies such as Infra-red thermography and laser technology. As a result of these adoptions and applications, the potential for Artificial Intelligence in construction sector has not only became an important focus of AI and robotic specialist, but also investors and forward-thinking managers in construction industry. From both economical, technical and managerial perspectives it is essential to understand how will the disruptive AI and Unmanned technology impact the future of construction industry and its work forces?
This presentation will focus on the implications and value to the integration of unmanned systems and AI in the construction industry with some key learning objectives Spsuch as:
Reviewing the trends for drone technology applications in construction
Recognizing the pitfalls and benefits inherent to adopting disruptive innovation such as Artificial Intelligence (AI) within the construction sector
Recognizing some of the operational risks and challenges unique to construction projects
Measuring the value from the applications of unmanned systems throughout the life cycle of construction projects
Visualization of Local Municipal Satisfaction by Twitter Data Analysis
Farzaneh Zarei, Amin Hammad, Mazdak Nik-Bakht
Mrs. Farzaneh Zarei (Presenter) Dr. Amin Hammad Dr. Mazdak Nik-Bakht, Concordia University
One of the most important factors in evaluating the performance of boroughs in a city is the satisfaction level of the residents with respect to municipal services. Social networks provide an extensive platform for local residents and communities to express their ideas about the level of service they receive, their problems and their expectations. In this paper, the level of satisfaction of people in different boroughs of Montréal is quantified by analyzing their tweets. In this aim, 3,293 tweets from January 2009 to March 2018 were collected. Then, the implicit viewpoint behind each of them was evaluated via human knowledge approaches. Hence, not only a valid data set was obtained for future automation, but also sufficient information was gained for visualizing and comparing the levels of satisfaction of several services in different boroughs. The results show that Verdun Borough provides more satisfaction to its residents. In spite of the limitations of the heterogeneity of Twitter users and their spread in a city, and the biases that might be associated with the tweets’ analytics, our results can add an extra layer to the evaluation of the level of service in cities. Overlaying such results with other performance indicators can lead to significant lessons for governance of smart cities.
A CASE STUDY OF CLIENT DRIVEN EARLY BIM COLLABORATION
Muhammad Tariq Shafiq
This paper presents a case study of client-driven early BIM collaboration, where the client mandated the BIM and employed an independent BIM consultant to ensure successful implementation of BIM throughout all project stages. The case study demonstrates the idea of achieving maximum benefits of BIM by initiating a coordinated modelling process, in early project stages, using a partnering approach in a traditional procurement process. This approach also encouraged early involvement of the contractor in the design process and ensured interoperable modelling & collaboration process in a structured common data environment that continued throughout the project stages supporting several BIM applications. The author was part of the client’s BIM consultancy team that was tasked to ensure that an integrated and coordinated BIM process is successfully developed at the early design stage that would continue throughout the construction and facility management stagesThis paper presents a case study of client-driven early BIM collaboration, where the client mandated the BIM and employed an independent BIM consultant to ensure successful implementation of BIM throughout all project stages. The case study demonstrates the idea of achieving maximum benefits of BIM by initiating a coordinated modelling process, in early project stages, using a partnering approach in a traditional procurement process. This approach also encouraged early involvement of the contractor in the design process and ensured interoperable modelling & collaboration process in a structured common data environment that continued throughout the project stages supporting several BIM applications. The author was part of the client’s BIM consultancy team that was tasked to ensure that an integrated and coordinated BIM process is successfully developed at the early design stage that would continue throughout the construction and facility management stages.
Application of Laser Scanning Technology in Energy Analysis and Structural health monitoring of Heritage Buildings
Mohamed Marzouk, Mahmoud Metawie, Maryam Sharkawy, Asmaa Eid, Soheir Hawas
Dr. Mohamed Marzouk, Cairo University (Presenter) Mr. Mahmoud Metawie, Cairo University Ms. Maryam Sharkawy, Cairo University Ms. Asmaa Eid, Cairo University Dr. Soheir Hawas, Cairo University
Integrating Building Information Modeling (BIM) with 3D laser scanning (LIDAR) technologies enhances the process of documenting heritage buildings. Many efforts were directed toward utilizing these technologies in the documentation and restoration of heritage buildings, adopting Heritage Building Information Modelling (HBIM). This paper presents a framework for HBIM application in Egyptian Heritage. The proposed framework is capable to utilize the processed point clouds to create different purpose BIM models at the different levels of development to suit the different applications in heritage buildings. It is capable to analyze the different parameters that affect the thermal behavior of the heritage buildings to identify the most suitable energy optimized strategies and techniques. Further, it simulates the structural performances under different types of actions. The proposed framework provides a guideline for heritage buildings conservation. The guideline can be integrated through a holistic approach that would encounter both safety and comfort without the compromise of the loss of heritage identity. A case study of Omar Tosson palace is presented to illustrate the practical aspects of the proposed framework.
ArcSPAT: An integrated BIM-GIS model for site layout planning
Ahmad Alsaggaf, Ahmad Jrade
Mr. Ahmad Alsaggaf, University of Ottawa (Presenter) Dr. Ahmad Jrade, University of Ottawa
Site layout planning (SLP) is an essential step for having a productive, efficient and safe construction environment. A well-planned construction site helps in increasing the productivity and safety of construction operations and in reducing the overall cost and duration of construction projects. The main purpose of SLP is to manage the available spaces on construction sites and to select the most appropriate location for placing temporary facilities (TF) needed to complete a project by considering all constraints that exist between different TFs and their relationships to permanent facilities (PFs). Due to the wide range of factors and variables and the complexity included in the process of site layout planning, most of the models discussed in the literature provided solutions to the site layout planning based on wide variations in their scopes, objectives, and approaches. As a result, authors were not able to find in the literature a complete solution to site layout problems. This paper proposes an integrated BIM-GIS methodology to develop a comprehensive, flexible, and practical SLP model to assist professionals to make informed decisions and apply their knowledge to solve the problems associated with the SLP’s process. It will also, highlights the potential of providing alternatives that may lead to a unified solution for SLP, which accommodates solutions supplied by other models presented in the literature that serves as a foundation to solve future problems through a more detailed research in this area. The proposed model consists of six modules, 1) a 3D modeling module, which links both BIM and GIS tools; 2) a route planning module that estimates the number of trucks (RPENT) for loading and hauling; 3) an execution schedule time entry (ESTE) module that facilitates the daunting and time-consuming process of creating a 4D model; 4) a 4D modeling module, that simulates the construction progress and helps in placing the TFs on the right locations on site ; 5) a temporary facilities library (TFL) module, which is developed to facilitate the selection of TFs, modeling and planning the construction site; and 6) a dynamic conflict detection (DCD) module that uses a smart detection tool to forecast potential conflicts and clashes on a construction site that would notify users about detected conflicts through an automatically generated report holding detailed information. The proposed model will assist site planners in planning construction sites that are safer, closely free of conflicts and that would reduce the project’s overall cost.
Big Visual Data Analysis for Building Information Modeling
Cheng Zhang, Fangyu Guo, Lei Fan, Yousif Ali
Dr. Cheng Zhang, Xi'an Jiaotong-Liverpool University (Presenter) Fangyu Guo Dr. Lei Fan, Xi'an Jiaotong-Liverpool University Mr. Yousif Ali
The Big Data concept is now receiving remarkable attention for tackling complex engineering problems. Among different engineering fields, Big Data analytics is notably impacting the Civil Engineering domain. However, despite the significance of the Big Data technologies to process large-scale data, current Civil Engineering information systems are still lacking in successful implementation of them. Big Data include all kinds of data that can be collected by different means, such as sensors, cameras, laser scanners, etc. Among those big data, visual data have better accessibility and have more impressions on human being’s daily life. The ever increasing volume of visual data due to recent advances in smart devices and camera-equipped platform provides an unprecedented opportunity to visually capture actual status of the physical environment at a fraction of cost compared to other alternative methods. This provides an unprecedented opportunity to understand the construction processes, but also requires advanced management skills and data-processing ability.
This paper investigated methods to collect on-site data using different technologies, and how those data can be fused into an information modeling platform, including geometric and sematic information. During the data acquisition stage, key questions will be investigated and answered. For example, What to collect? How to collect? In which form? For what purpose? How to use? A sequential and automatic framework is developed to analyze those data, which includes Image Registration, Image Feature Extraction, Object Shape Detection, and Object Updating/Tracking (static/moving object). Meanwhile, semantic meanings will be integrated into the information model, where the data collected as attributes will be processed and associated with corresponding components in the geometric models. Semantic enrichment of building models adds meaningful domain-specific or application-specific information to a digital building model. Algorithms are developed to identify different materials and components based on data collected. A case study is applied on a construction site by collecting visual data and integrating the processed information into a BIM model. Preliminary results show that more efforts should be contributed in building a roadmap based on big visual data analysis, where raw data need to be filtered, extracted and summarized into domain-related information and build information models for the entire built environment.
BIM for Temporary Structures: Development of BIM API Plug-ins for Concrete Formwork
Ziyu Jin, John Gambatese
Ms. Ziyu Jin, Oregon State University (Presenter) Dr. John Gambatese, Oregon State University
As one of the most promising developments, Building Information Modeling (BIM) enables the possibility of automating the design process. Prior research efforts have largely focused on permanent design components with minimal attention given to temporary structures, such as concrete formwork and scaffolding. Nevertheless, the design processes for temporary structures are repetitive and often tedious, which require consideration of multiple parameters of individual permanent components, the latest design standards, design methods, procedures, and available materials. This paper proposes a BIM-based tool to help with planning and designing concrete formwork. The tool integrates the information associated with individual elements in BIM models with design processes recommended by the American Concrete Institute (ACI) through an Application Programming Interface (API) in BIM extension. Using the tool, planners will be able to decide the most applicable formwork design based on the design of the permanent facility along with the availability of construction materials, site conditions, and safety considerations. The research also provides a new tool for contractors when planning concrete operations and extends the BIM design scope.
BIM-based code compliance checking for fire safety in timber buildings: A comparison of existing tools
Kristina Kincelova, Conrad Boton, Pierre Blanchet, Christian Dagenais
Ms. Kristina Kincelova (Presenter) Mr. Conrad Boton Mr. Pierre Blanchet Dr. Christian Dagenais, FPInnovations
The nature and the complexity of building codes, including the fire regulations, result in mainly manual verification and, therefore, in subjective potential interpretations or errors. In the case of timber construction, the fire safety regulations are moreover a challenge due to the combustibility of the material. Further integration of fire safety is needed during the design process in order to increase the reliability of the designs in terms of fire safety. Building information modelling (BIM) technologies offer today new tools for automating different tasks in the construction process. The different approaches and available tools have been therefore compared in the context of fire protection code compliance. For that matter, criteria applicable to the tools have been identified based on literature review and on the National Building Code of Canada prescriptive provisions, but also based on a practical manipulation of the available tools. The potential of the different tools is therefore assessed based on their integration of the fire protection concepts and on their adaptability to BIM. This contextualized comparison has shown that the fire protection integration in BIM is limited. The tools for performance-based fire protection design are not exploring enough the information contained by the building model that is beyond the geometry. The BIM-based compliance checking tools, in turn, contain insufficient space for fire safety regulations checking as advanced spatial study is required for this purpose. Thus, this paper demonstrates the need for further development in terms of exploiting the building modelsâ€™ semantics in the fire protection context.
The BIM impacts on stakeholder management in airport construction projects
Tais Scherer, Forgues Daniel
Ms. Tais Scherer, École de technologie supérieure (Presenter) Dr. Forgues Daniel, Ecole de technologie supérieure
Airports are complex and dynamic, a multiple stakeholder environment which demands a great effort from the project actors when running an infrastructure intervention. Developing strategies to manage stakeholders within the project activities is fundamental to achieve project goals, especially concerning to the decision-making process, which in airports should be as assertive as possible due to the numerous interferences a project can have on their operations. This is where new technologies like Building Information Modeling (BIM) assume its strategic role, contributing to the project providing good quality information that helps the decision makers. The assumption of this study is that, with better-quality information, the communication process will be improved, helping to efficiently manage stakeholders during the project. To verify this impact on stakeholder management when running projects with BIM, a case study was chosen, and a series of semi-structured interviews were made with the main airport stakeholders, internal and external to the project. The findings from the interviews were combined with concepts from previous research on the airport industry, construction industry and project management, focused on stakeholder management, to come up with the results of this study. The final result suggests an improvement of stakeholder management achieved by: a significant improvement on understanding, since BIM might create a common language that align all stakeholders’ perception about the project; a creating of a collaborative environment that allows trustful relationships be built; a creating of a sense of project ownership, promoted by a creating of an airport project community; an improved engagement due to the better understanding, the collaborative environment, the community sense. These findings were validated with two specialists in airports domain. Future research could embrace the aspect of organizational and individual behavior and resistance to change impacting to achieve the full benefits of BIM technologies concerning stakeholders’ management.
Workplace Experiences for Women and Men using BIM/VDC in Construction
Girija Inguva , Caroline Clevenger, Mehmet Ozbek, Moatassem Abdallah
Ms. Girija Inguva , University of Colorado Denver Dr. Caroline Clevenger, University of Colorado, USA (Presenter) Dr. Mehmet Ozbek Dr. Moatassem Abdallah, University of Colorado, Denver, USA
The use of Building Information Modeling or Virtual Design and Construction (BIM/VDC) in construction is prompting cultural change in the construction industry. This research presents survey results documenting differences in self-perceived workplace experience for workers whose duties include the use of BIM/VDC and workers whose do not. Further breakdown of results is presented for women and men and organizations with and without specific BIM departments. Findings suggest that, overall, individuals who use BIM/VDC perceive more benefits than barriers. Specific findings suggest that individuals see most benefit related to leading change, having greater access to technology and more educational opportunities. Career barriers generally relate to being siloed as an employee, and not having a clear career path. Findings related to both benefits and barriers can differ across gender. The contribution of the research is to provide statistical and descriptive insight into the impact of BIM/VDC on workplace experience. Such information is valuable to construction leaders and researchers interested in promoting, implementing, and studying the adoption of such technology in construction practice.
BIM and AI
APPLICATIONS OF BIM AND UAV TO CONSTRUCTION SAFETY
Yuting Chen, Jiansong Zhang, Byung-Cheol Min
Ms. Yuting Chen, University of Toronto (Presenter) Dr. Jiansong Zhang, Purdue University Dr. Byung-Cheol Min, Purdue University
Building information modeling (BIM) and unmanned aerial vehicle (UAV) have shown a potential to improve construction safety performance. As new technologies, they are in an early adoption stage in the construction industry. It is still not clear what is the application status of UAV to construction safety or how BIM and UAV are working together to serve as a safety inspection tool. Therefore, this paper conducted a preliminary literature review to identify the current research and application status of BIM and UAV to construction safety. It was found that there are two approaches in the literature in terms of using UAV and BIM for construction safety. In approach 1, UAVs are used to collect geometric data of construction sites to visualize current site conditions in BIM, based upon which potential safety issues can be identified. In approach 2, BIM with the aid of experienced safety experts can provide potential safety hazard locations, and then flight routes of UAVs can be generated accordingly. In the end, this paper proposed a loop system integrating approach 1 and 2.Â
Framework for Cost Estimation Using BIM Object Parameters
Michael Clark, Hani Alzraiee
Mr. Michael Clark, California Polytechnic State University, San Luis Obispo (Presenter) Dr. Hani Alzraiee, California Polytechnic State University
This paper proposes a framework to conduct a quantity take-off (QTO) and cost estimate using a Building Information Model (BIM). The method addresses the cost uncertainty associated with the detailed information that defines the design geometry and properties (BIM objects). For example, estimating a concrete wall is impacted by parameters subjectively defined and quantified by construction estimators. Wall height, reinforcing, and block-outs for openings all affect the price per unit area of a concrete wall, these factors are not captured by current BIM estimating practices. In addition, cost estimators have little experience in utilizing and leveraging information within semantic-rich information models. This is due to the lack of available tools that address detailed QTO and cost estimation using a BIM platform. Parameters impacting BIM objects are considered a source of uncertainty in the cost estimate, therefore they should be identified and quantified.
A system which assists the estimators to conduct a QTO and cost estimate within the BIM environment is developed. This system addresses the BIM model generated quantities, BIM object parameters, and cost of scope not captured in BIM. The system consists of five modules 1) BIM representing design objects; 2) project costs classification module; 3) object parameters library; 4) computation platform; and 5) updating the estimate model and parameters during construction. The BIM represents the design objects with their properties. For each object, the parametric factors impacting cost are identified, quantified and mapped into their objects. Since not all project costs are represented within the BIM model, project cost drivers are classified as internal and external to the BIM. The computation platform consisted of Autodesk Revit to document quantities, Autodesk Dynamo to associates parameters with quantities, and excel to assign external costs. The last step involved a real-time update of the object cost parameters to calibrate the system for project controls and future use.
The developed method was tested using real residential project data from the construction sector. The early results showed using BIM to conduct project cost estimating without considering the object’s parameters that impact cost is a real source of risk and can lead to inaccurate project cost estimate, and hence misleading project controls metrics.
The Adoption of Building Information Modelling in Canada
Li Hao Zhang, Yuan Cao, Arash Shahi, Brenda McCabe
Mr. Li Hao Zhang, University of Toronto Ms. Yuan Cao, University of Toronto Dr. Arash Shahi, University of Toronto (Presenter) Dr. Brenda McCabe, University of Toronto
In 2017, the First Annual BIM Survey was disseminated across the Greater Toronto Area as a pilot project to understand the local adoption of Building Information Modelling (BIM) in the Architecture, Engineering and Construction (AEC) industries. Technical analyses for the 2017 survey were presented in the 2018 CSCE Conference in New Brunswick and the summary of results were published in a technical report, which can be found on the Building Tall Website (http://buildingtall.utoronto.ca/). In 2018, the Second Annual BIM Survey was conducted in collaboration with RESCON, Canada BIM Council, BuildingSMART Canada, and local BIM chapters to engage AEC professionals across Canada. In this paper, sample results of the Second Annual BIM Survey are presented and benchmarked against those in the first survey. An in-depth discussion of the perceived benefits and barriers for adopting BIM in Canada are also provided. This study serves as one of the milestones of the BIM transition process in Canada and aims to present a detailed view of the role that BIM plays in the future of the industry.
Utilization and Implementation of E-Ticketing to Electronically Track the Delivery of Construction Materials
Behzad Rouhanizadeh, Sharareh Kermanshachi
Mr. Behzad Rouhanizadeh, University of Texas at Arlington Dr. Sharareh Kermanshachi, University of Texas at Arlington (Presenter)
With rapid advances of data technology and internet within recent years, implementation of E-Ticketing has increased in different areas such as inspection activities in construction projects. By utilizing sufficient software and electronic systems, electronic track of construction material delivery becomes possible, which leads to many benefits such as cost reduction, greater transparency, productivity improvement, etc. For example, E-ticketing could be useful in tracking delivery of construction materials such as concrete by providing haul report, travel time, tonnage of the material as well as enrichment of the records of the project. In this study, different characteristics and barriers of implementing E-Ticketing for tracking construction materialsâ€™ delivery were investigated and an integrated framework for monitoring the delivery process to achieve efficient inspection approach was developed. For this purpose, different E-Ticketing implementation strategies were described and then the challenges and solutions for successful E-Ticketing implementation for material delivery were expanded and studied. This paper contributes to assist service providers which intend to implement E-Ticketing to successfully adopt this service to their system.
APPLICATION ET EFFICACITÉ DU PLAN DE GESTION BIM (PGB) POUR LA CONSTRUCTION D'UN CENTRE HOSPITALIER DE GRANDE ENVERGURE AU QUÉBEC
Marc-Yvan Quenneville, Conrad Boton, Forgues Daniel
Mr. Marc-Yvan Quenneville, École de Technologie Supérieure (Presenter) Mr. Conrad Boton Dr. Forgues Daniel, Ecole de technologie supérieure
Selon plusieurs statistiques, la productivité de l’industrie de la construction stagne et peine à croitre pour un ensemble de raison. L’une des solutions à ce problème est l’utilisation du Building Information Modelling ou BIM. Plusieurs recherches ont été réalisées sur les bénéfices potentiels de l’approche, mais beaucoup moins sur l’application de cette dernière. La recherche est d’autant plus nécessaire que la méthode est considérée comme étant en rupture avec les processus connus et actuellement utilisés par une très grande proportion de l’industrie. Plusieurs professionnels et organismes ont développé un outil pour gérer le BIM sur les projets : le plan de gestion BIM (PGB). Cependant, les développements dans le domaine ont été réalisés à la pièce sans réelle cohésion sur une méthodologie très disparate. Ainsi, le présent projet de recherche vise donc à étudier les enjeux et les problématiques liés à l’utilisation du PGB dans une situation réelle de gestion de projet au Centre Hospitalier Universitaire de Québec (CHUQ).
Pour ce faire, il a été nécessaire de comprendre la mécanique liée à l’implémentation du BIM sur un projet, explorer ce qu’est un PGB (définition, objectifs, contenu), connaitre les différents enjeux liés à son application par la littérature et valider la véracité de ce dernier point en questionnant les acteurs qui appliquent ce genre de méthode.
Pour être en mesure de répondre à ces objectifs, une recherche en profondeur de la littérature a été réalisée pour bien comprendre l’implémentation de la démarche. Par la suite, pour être en mesure de qualifier la véracité des informations trouvées, le PGB utilisé sur le projet sera étudié, des intervenants seront rencontrés en solo ainsi qu’en groupe pour être en mesure de dresser un portrait réel de la situation.
Les données recueillies durant les entrevues permettront de tirer des constats sur la situation actuelle des problématiques ainsi que des enjeux et permettront d’établir des pistes de recommandations sur le PGB en fonction de certains constats dans le but d’améliorer la situation, faire avancer les connaissances sur cette méthode de gestion et ultimement aider à son déploiement.
Criticality Assessment of Hospital Building Systems
Reem Ahmed, Tarek Zayed
Mrs. Reem Ahmed, Concordia University (Presenter) Dr. Tarek Zayed, Concordia University
Healthcare facilities are one of the most important assets in a country as their number and quality is a common measure of the society’s prosperity and quality of life. Healthcare facilities include a wide range of types including: medical clinics, dental offices, nursing homes, birthing centers, hospitals and out-patient surgery centers.
Hospitals are the biggest facilities compared to other facility types and are the most complex to operate and maintain as they should work 24/7 with maximum performance and any mistake could cost the lives of many humans at a time. Hospitals also employ a wide variety of trades from medical staff, to maintenance staff, housekeeping, food service and administrative staff which makes it even harder to coordinate and facilitate the operation and maintenance of the facility.
Although Canada is one of the highest countries all over the globe in the health spending, the Canadian healthcare system and facilities are one of the lowest performers among developed countries. The status of the Canadian hospitals was described in many reports and statistics as a crumbling status as their overall condition received a “POOR” grade based on their deferred maintenance and current replacement values. This can be associated with the maintenance strategies implemented inside the facilities which are preventive (scheduled) and reactive maintenance (run-to-fail).
As a result, this paper recognizes the need to implement a predictive maintenance strategy instead of the currently implemented approaches to increase the performance of hospital buildings and efficiently make use of the funds assigned for healthcare facilities.
This paper assesses the criticality of the various hospital systems and creates a prioritized framework to help optimize the allocation of available funds. Experts were interviewed regarding this matter and their opinions were analyzed using multi-criteria decision-making tools and techniques to evaluate the weight and importance of all hospital systems using pair-wise comparison methods, representing the relative effect of the various systems on the total hospital performance.
The interdependence of the hospital systems was not employed before in the literature which is considered a novelty of this research. The proposed framework can be used by facility and maintenance managers to facilitate the decision-making process regarding maintenance, repair, replacement and renovation activities of hospital buildings and healthcare facilities.
Elemental Graph Date Model (EGDM) Significance: Constructability Information Extraction
Yasmeen Essawy, Khaled Nassar
Mrs. Yasmeen Essawy, The American University in Cairo (Presenter) Dr. Khaled Nassar, American University in Cairo
With the rapid increase in complexity in the building industry, professionals in the A/E/C industry were forced to adopt Building Information Modeling (BIM) in order to enhance the communication between the different project stakeholders throughout the project life cycle and create a semantic object-oriented building model that can support geometric-topological analysis of 3D building elements during design and construction.
This research presents a model that extracts topological relationships and geometrical properties of building elements from an existing fully designed Building Information Model (BIM Model), and maps this data into a directed acyclic Elemental Graph Data Model (EGDM). The model incorporates BIM-based search algorithms for automatic deduction of geometrical data and topological relationships for each building element type. Using advanced graph algorithms and artificial intelligence tools, such as Depth First Search (DFS) and topological sorting, possible construction sequences are generated and compared against production and construction rules to generate an optimized construction sequence. The model accounts for any customized user-defined relationships in order to mimic any practical constraints. Finally, the model recommends the Optimized Elemental Construction Method, Schedule & Resources, and, hence, generates 4D BIM models. The model is implemented in a C# platform and validated with the aid of a set of automatically generated test cases.
The Implementation of Building Information Modeling (BIM) Towards Sustainable Construction Industry
Amira E. Mohamed, Mohamed N. Abou-Zeid
Ms. Amira E. Mohamed, The American University in Cairo, AUC Dr. Mohamed N. Abou-Zeid, The American University in Cairo (Presenter)
Global environmental changes, energy consumption, and the scarcity of water have all imposed the need to implement sustainable development strategies worldwide. The construction industry and its healthy practices are not exception, as it should take more strides to alleviate harmful impacts of unsustainable construction practices on the built environment. Sustainable construction has many aspects such as passive design, selection of the appropriate materials and construction techniques, energy efficient systems, and water conservation.
The construction industry is a multi-disciplinary industry that includes all the built environment elements like infrastructure, workspaces, housing, utilities, and transportation. Also, the construction sector has a high economic impact and serious environmental and social concerns.
The significant contribution of the industry on the built environment is urging the Architecture, Engineering, and Construction (AEC) professionals to convert current conventional construction approaches into more sustainable ones. One of the useful in this regard is to capitalize on an innovative technological means to narrow the gap and advance the sustainable green construction mission. Building Information Modeling (BIM) is a relatively recent technology within the construction industry that, when properly introduced, can help in providing adequate project quality, accurate time and quantity take-offs schedules, and project costs reduction. For instance, this tool can result in more efficient design practices, which contribute to reducing waste generation, energy consumption and promote passive design strategies.
This study aims at analyzing the impact of BIM implementation on the sustainable construction practices and assessing current BIM implementation trends during the design process phase in the AEC industry. In principle, the study tackles BIM adoption situation factors of influence, barriers, and opportunities confronting its implementation within consultancy firms. Building on the literature review, this study discusses the sustainable design and constructability concepts in the construction industry and how BIM can be effectively utilized the pre-construction phase. Furthermore, the study describes the BIM implementation obstacles, success factors, and the role of government and other stakeholders in adopting BIM for achieving sustainable construction industry. In addition, interviews were conducted with BIM experts to investigate the BIM implementation situation in the Egyptian consultancy firms and the needed actions for successful BIM adoption strategies that can be applicable for the Egyptian construction market and other markets worldwide.
Key words: Sustainable development, Building Information Modeling, (BIM), BIM adoption strategies, Sustainable Strategies, Benefits, Risks and Challenges.
Case Studies in natural hazards risk assessment of civil engineering systems
Assessment of Resilience of Water Distribution Network against Seismic Hazards for Maintenance Planning
Sudipta Adhikary, Fuzhan Nasiri, Ashutosh Bagchi
Ms. Sudipta Adhikary, Concordia University (Presenter) Dr. Fuzhan Nasiri, Concordia University Dr. Ashutosh Bagchi, Concordia University, Canada
It is essential that water distribution networks (WDNs) remain performing undeviatingly following constrained to natural hazards, and it is considered vital in terms of seismic hazards, to keep maintaining structural integrity. Several studies on past earthquakes occurred in Vancouver, BC, have prompted notable destruction to WDNs, interpreting them as a potential reason for loss and damage from structural and economic perspective. Based on the behavior of underground water distribution pipelines, this paper suggests a method to quantify resiliency as easy-to-use metrics to improve the performance of water distribution network subjected to earthquakes. In cities like Vancouver, WDNs are prone to seismic hazards and are subject to regular refurbishment and repair. Following such circumstances, early evaluation of existing networkâ€™s seismic structural resilience is essential to carry out strategic planning for maintenance and replacement works. In this paper, resilience index is produced for the WDN of the study area (an extensive network consisting of 69,680 links) considering three scenarios of earthquakes ranging between MMI 7 to MMI 10 (very strong to severe). These scenarios are formed using empirical data of past earthquakes, which includes ground motion and break rates of lifelines and the estimated peak ground acceleration (PGA). All the neighborhoods in the study area are ranked from most resilient to least resilient based on index metrics. Maintenance scenarios for the least resilient neighborhood due to the extreme exposure of the event have been produced as maintenance map to improve the resiliency of the system, integrated with the geographical location using software ArcGIS. To build a practical and feasible replacement strategy, 12 maintenance planning with network map is created showing an increase ranges from 0.8% to 41.52% in the total resiliency of the network and an estimated 15.17% to 89.96% increase of the invulnerability in the network mains. Taking cost as a vital limiting agent in the replacement of WDNs, afterward, evaluation of robust replacement alternatives are performed to find out a cost-effective maintenance planning strategy.
Scénarios de risque sismique d'un réseau municipal de ponts pour l’évaluation des impacts économiques
Hamza Fezai, Nollet Marie-José, Ahmad Abo-El-Ezz
Mr. Hamza Fezai, Ecole de technologie superieure (Presenter) Dr. Nollet Marie-José, École de technologie supérieure Dr. Ahmad Abo-El-Ezz, Geological Survey of Canada, Natural Resources Canada
Auteurs : Hamza Fezai, Marie-José Nollet, Ahmad Abo-El-Ezz.
Dans des régions qui sont sujettes aux tremblements de terre, les dommages aux ponts peuvent entrainer une perte de fonctionnalité du réseau routier. Par conséquent, l’évaluation sismique des ponts est cruciale pour établir des stratégies d’intervention et rétablir les réseaux routiers afin d’assurer le maintien des services essentiels tels que l’accès aux hôpitaux et l’acheminement des secours.
Néanmoins, pour créer un système de gestion efficace et performant et optimiser le processus décisionnel, il est important d’étudier l’impact de scenarios sismiques sur l’état du réseau et sur les pertes économiques. L’objectif du projet est d’utiliser les résultats de scénarios sismiques pour identifier rapidement l’état de dommage, le cout de réparation et le niveau de fonctionnalité des ponts sur un réseau municipal. Quatre étapes sont proposées dans ce projet. La première étape consiste à interpréter un modèle de risque sismique générant une distribution spatiale de l'intensité de tremblement de terre pour différents scénarios sismiques. La deuxième étape est de construire une base de données des ponts selon des classes définies en fonction des matériaux de construction, du comportement sismique et des systèmes structuraux. La troisième étape est d’évaluer la performance sismique des ponts du réseau selon des données de fragilités respectives aux différentes classes de ponts. La dernière étape utilise les résultats de l’étape précédente pour définir un modèle d’impact qui représente l’état du trafic routier selon la distribution et l’importance des dommages et l’estimation du coût de réparation. Ces données sont ensuite utilisées pour planifier les inspections après séisme du réseau de ponts.
L’approche intègre les incertitudes sur les données de fragilité et sur l’intensité du séisme du scénario considéré.
The use of HazCan to assess the earthquake risk of residential buildings in Montreal, Canada
Philippe Rosset, Morley Kert, Youance Suze, Nollet Marie-José, Luc Chouinard
Dr. Philippe Rosset, McGill University Mr. Morley Kert, University McGill Mrs. Youance Suze, Département de génie de la construction, École de technologie supérieure, Université du Québec Dr. Nollet Marie-José, École de technologie supérieure (Presenter) Dr. Luc Chouinard, McGill University
Montreal is the second most vulnerable city for earthquakes, after Vancouver, considering the level of the seismic hazard level and the population. A study, supported by the Ministère de la Sécurité Publique du Québec, has been conducted to assess the losses to residential buildings for several earthquake scenarios. Population and building data have been collected for each of the 3'201 dissemination areas forming the Montreal Island. Inventory of the buildings in terms of occupancy and construction types uses mainly the information for about 350'000 buildings available in the 2016 municipal property roll of Montreal. Wood-frame buildings counts for 79% of the total, masonry for 18%, steel frame and reinforced concrete sharing the last 3%. Ground motion prediction equations for Eastern North America are applied for the different seismic scenarios taking into account microzonation in terms of Vs30 derived soil classes. Depending on the scenario, damage ranges from 25 to 60% of the building stock, severely damaged and collapsed buildings representing 2 to 12% of the total. Non-structural damage accounts for 80% of the total losses. Generally, masonry houses built before the 20th century account for most of the damage as wood-frame structure perform best. The total losses vary between 1 and 12% of the portfolio for residential houses depending on the selected scenario. Preliminary estimates of the amount of debris generated by scenario earthquakes range from 0.6 to 6 million tons, with brick and wood debris representing approximately 60% of the total.
WIND LOADS ON CANOPIES ATTACHED TO WALLS OF LOW BUILDINGS
Faruk Ahmed Sakib, Zannatul Mawa Dalia, Ted Stathopoulos, Anjan Bhowmick, Hatem Alrawashdeh
Mr. Faruk Ahmed Sakib, Concordia University (Presenter) Mrs. Zannatul Mawa Dalia, Concordia University Dr. Ted Stathopoulos, Concordia University Dr. Anjan Bhowmick, Concordia University Mr. Hatem Alrawashdeh, Concordia University
Overhangs are commonly used in residential and industrial buildings for the convenience of residents and users. These overhangs can be found with different names such as building eaves, patio covers, canopies, awnings or porches. In most cases, practitioners and designers struggle to evaluate design wind loads for canopies because wind standards and codes of practice only rarely refer to provisions of wind-induced pressures for their design. However, canopies are very prone to wind due to the suction developing on their upper surface along with the pressure occurring on their lower surface (for most wind directions), which together may generate critical uplift forces causing lots of damage on these elements under strong winds.
The paper refers to the results of a study collecting all available literature research data originating from wind tunnel experiments simulating adequately the natural wind conditions. Comparisons of the results with a few computational evaluations, as well as the limited provisions of codes and standards show significant discrepancies that are discussed in detail. Some of these differences are due to the various configurations used in the previous studies, e.g. geometry, size and slope of overhangs, specific location on the wall(s), existence of openings, as well as roof shape (flat, gabled or curved / arched). This topic is very timely due to the new canopy pressure coefficient provisions included in the ASCE 7 (2016) version of the American standard and the upcoming 2020 edition of the National Building Code of Canada. The paper will discuss the origin of these provisions, the extent of their applicability, as well as the common errors designers may make by using, for instance, internal pressures from other sections of the code(s) or by neglecting the critical effects of wind direction given that some of these literature values are validated for a single wind direction.
Finally, a review of the current activities on this area, as part of our program on wind engineering and building aerodynamics at Concordia University will be presented.
Case Studies in natural hazards risk assessment of civil engineering systems
A Web application for rapid seismic risk assessment
Ahmad Abo-El-Ezz, Alex Smirnoff, Miroslav Nastev, Nollet Marie-José, Heather McGrath, Nicholas Gibb
Dr. Ahmad Abo-El-Ezz, Geological Survey of Canada, Natural Resources Canada (Presenter) Mr. Alex Smirnoff, Geological Survey of Canada, Natural Resources Canada Dr. Miroslav Nastev, Geological Survey of Canada Dr. Nollet Marie-José, École de technologie supérieure Ms. Heather McGrath, Canada Centre for Mapping and Earth Observation, Natural Resources Canada Mr. Nicholas Gibb, Geological Survey of Canada, Natural Resources Canada
Numerous computer models have been developed for seismic loss analyses at urban and regional scales. They seem, however, ill-suited to custom application to the specific Canadian hazard and exposure settings and, more importantly, inadequate for utilization by the broader non-expert public safety community. Therefore, communication of the potential seismic risk results to local stakeholders, such that they can properly understand their exposure and vulnerability, represents an outstanding challenge. The objective of the present study is to describe the methodological background and ongoing development activities of the Rapid Risk Evaluator (ER2), a relatively rapid and user-friendly risk assessment application, developed to overcome the current communication barriers between risk experts and decision makers. Developing ER2 included: pre-computing site-specific databases containing ground motion scenarios, prediction of potential attenuation with distance and local site amplification, a standardized inventories of buildings’ structural properties and occupancy categories, and assessment of the seismic vulnerability using hazard-compatible vulnerability functions. These functions correlate directly the intensity of the seismic shaking to the probability of damage and direct economic and social losses. This approach allows for conducting risk scenarios in large urban centers within minutes. The above approach was programmed into an easy to run web-application. Equipped with graphic user interface, ER2 allows non-expert users to run otherwise complex seismic risk scenarios through a simple intuitive selection process. An example of ER2 applied to a hypothetical earthquake event in Quebec City is included to illustrate the simplicity of the user interface and capabilities of the application.
ER2- Flood: A Web Application for Rapid Flood Risk Assessment.
Heather McGrath, Nicholas Gibb, Alex Smirnoff, Jean-François Bourgon, Jean-Samuel Proulx-Bourque, Miroslav Nastev, Ahmad Abo-El-Ezz
Ms. Heather McGrath, Canada Centre for Mapping and Earth Observation, Natural Resources Canada Mr. Nicholas Gibb, Geological Survey of Canada, Natural Resources Canada Mr. Alex Smirnoff, Geological Survey of Canada, Natural Resources Canada Mr. Jean-François Bourgon, Canada Centre for Mapping and Earth Observation, Natural Resources Canada Mr. Jean-Samuel Proulx-Bourque, Canada Centre for Mapping and Earth Observation, Natural Resources Canada Dr. Miroslav Nastev, Geological Survey of Canada (Presenter) Dr. Ahmad Abo-El-Ezz, Geological Survey of Canada, Natural Resources Canada
Many different models exist for natural hazard simulations, but due to their technical complexity and data requirements, their use is generally restricted to domain experts. As a result, there is often a lag in the communication of risk to the emergency management community. Rapid Risk Evaluator (ER2) is a web-based application that removes this impediment and puts risk assessment tools directly in the hands of the end users. The ER2-Flood prototype has been developed using open source software and Canada wide datasets, and it is envisioned it will be available for nationwide use. In this first iteration of ER2-Flood, the Height Above Nearest Drainage (HAND) model is used along with user-specified location and water depth to simulate the spatial extent of the flood and flood depth across the study area. The considered negative impacts include total count of buildings affected, economic losses, social impact (e.g.: population displaced), and disruptions to the transportation network. The prototype is currently being tested for the Gatineau area, using the 2017 flood as a base-case for validation. Preliminary results are similar to those obtained when running other risk assessment programs (e.g.: Hazus-MH), however, the ER2 runtime is considerably shorter, no user data is needed and it is a more automated process.
Case Studies in natural hazards risk assessment of civil engineering systems
A proposed assessment scheme for smart sustainable Urban Development
Ilham Elfiky, Mohamed N. Abou-Zeid, Alan Plattus
Ms. Ilham Elfiky, Mrs (Presenter) Dr. Mohamed N. Abou-Zeid, The American University in Cairo Mr. Alan Plattus, Yale University
A proposed Assessment Scheme For Smart Sustainable Urban Development
Ilham Elfiky*, Mohamed Nagib AbouZeid*, Alan Plattus**
*The American University in Cairo **Yale University, the USA
The twenty-one century belongs to the cities. For the first time in history, more than 50% of the world’s population now lives in a city and the urban population is expected to double by 2050. Cities are increasingly seen as the engines of sustainable development and the shift to low carbon economy. The growth of cities in the twenty- one century should depend on sustainable cities approach that utilizes Information and Communication Technology (ICT). The opportunities created by new technologies challenge the way in which we conceive our cities.
The current large gap between smart city and sustainable city frameworks implies that there is a need for developing their frameworks further or re-defining the smart sustainable city concept. Furthermore, standards like BREEAM or LEED does not cover all the topics behind the Smart Sustainable City concept. This paper provides a foundation for developing a framework for the planning of a Sustainable Smart City based on rigorous criteria and sub-criteria. This framework will be used to assess the smart sustainable urban development of the new administrative capital of Egypt, one of the most ambitious and important urban development projects at present in Egypt.
A qualitative methodology has been applied through a systematic review of the literature, aimed at sustainable development of smart cities which examines the terms, ‘smart city’ and ‘sustainability. Furthermore, the criteria have been selected according to international standards via ISO37120 and the International Telecommunication Union (ITU), the collective methodology for each indicator has been explained. In addition, panel discussions and direct interviews have been conducted in collaboration with the Yale Urban Design Workshop (YADW). This practice-based multi-disciplinary environment has allowed the interaction with other students and faculty for assessment of each criterion bringing together the natural behavioral and social sciences with engineering to articulate a holistic approach that is essential for our study.
Debates about environmental challenges are often hindered by lack of problem definition, uncertainty about the nature of these challenges, and ill-defined solutions. Gathering data into the recommended proposed framework helps to resolve these difficulties. City assessment tools can be used as support for decision making in urban development as they provide assessment methodologies for cities to show the progress towards defined targets.
Assessment of Hurricane Maria in the United States using CoBRA Model
Sai Akhila Boddi Reddy, Ingrid Arocho
Ms. Sai Akhila Boddi Reddy, Oregon State University (Presenter) Ms. Ingrid Arocho, Oregon State University
System resilience is defined as the ability of a system to prepare for hazards, adapt to changing conditions, and withstand and bounce back rapidly from a defined disruptive state. The key steps to resilience include prevention, protection, mitigation, response, and recovery. There are two types of resiliency plans: pre-disaster plans and post-disaster plans. The objective of this study was to compare the post-disaster plans used for hurricane Maria to the ones used for older hurricane Katrina in terms of severity, damage, and recovery. Hurricane Maria was selected due to the shorter amount of time from the disaster and the researchersâ€™ ability to gather enough information post-disaster. The methodology used to compare the hurricanes was Community Based Resilience Analysis (CoBRA) model. CoBRA was designed as a conceptual framework to assess and measure the impacts of drought risk reduction. This model was initially designed for droughts in the European countries. The researchers implemented the model by modifying key factors that typically affect communities during a hurricane. Participants from the communities that faced the disaster were selected to discuss the resiliency levels after the event. Required data was collected for the phases and steps included in the CoBRA assessment including utilities, transportation and communication systems. The results of this study give a better idea of how reacting to hurricanes changed over the years and to determine the efficiency of the resiliency plans. Recommendations were made based on the results to enhance the current resiliency plans and to improve the response and recovery rates post-disaster.
EVALUATING NATURAL HAZARD-INDUCED ELECTRICITY SECTOR INOPERABILITY LEVERAGING DATA-DRIVEN STATISTICAL LEARNING APPROACH
Soojin Yoon, Sayanti Mukherjee, Makarand Hastak
Mrs. Soojin Yoon, Construction Engineering and Management, Purdue University (Presenter) Dr. Sayanti Mukherjee, University at Buffalo Dr. Makarand Hastak, Division of Construction Engineering and Management, Purdue University
Our built environment is threatened with ever-increasing risks of climate change and natural hazard-induced extreme events. Under multi-hazard scenarios—such as floods, wildfires, droughts, heatwaves, etc.—the risk of severe weather-induced power outages is growing. Such weather–induced cascading power outages can cause tens of billions of dollars of economic loss. In this research, we propose an integrated approach to develop a composite predictive model framework for evaluating the inoperability of the utility sector in a multi-hazard scenario. Inoperability is defined as the level of utility sector’s service disruption (i.e., interruption to the power supply measured by power outage duration) caused by the severe weather events. The proposed framework consists of three main phases: (1) to select natural hazard-induced power outage events, (2) to develop separate models for each of the disaster categories as discussed before, and (3) to develop a composite predictive inoperability of the utility model by integrating the individual models developed in Phase 2. We leveraged data-driven semiparametric statistical learning model called generalized additive model (GAM) to develop the inoperability prediction model. The data on major power outage events in the continental U.S. between 2000 and 2016 is used to develop the model. Our proposed inoperability prediction model will allow the stakeholders and decision makers (e.g., the state regulatory commissions or the utility companies) to evaluate the extents of electricity sector inoperability, both under a single-hazard or a multi-hazard scenario. The model results will help in risk-informed decision-making for pre- and post- disaster resource allocation and capacity expansion investments to improve the security of the electricity sector as a whole.
Strategic assessment of current and future exposure of wildland human interface and communities to wildfire in Canada
Yan Boulanger, Sylvie Gauthier, Sandy Erni, Amy Christianson, Solange Nadeau, Brian Eddy, Lynn Johnston
Dr. Yan Boulanger, Natural Resources Canada (Presenter) Dr. Sylvie Gauthier, Natural Resources Canada Dr. Sandy Erni, Natural Resources Canada Dr. Amy Christianson, Natural Resources Canada Dr. Solange Nadeau, Natural Resources Canada Dr. Brian Eddy, Natural Resources Canada Mrs. Lynn Johnston, Natural Resources Canada
Wildland fires and human systems maintain a dynamic relationship driven by the successive interferences of one another. Interactions among climate, fuels, ignitions, and humans largely regulate wildfire activity, thereby determining where and under what conditions flammable landscapes burn. In the wildland-human interface (WHI, which includes the wildland urban interface [WUI], the wildland industrial interface [WII] and the wildland infrastructure interface [WInfI]), the imperative is often to protect life and property from destructive fires, while also conserving biodiversity. If burning represents a direct threat to human infrastructures, smoke from the combustion of biomass is also recognised to be harmful to human health and constitutes one of the primary risk factor leading to people evacuations. In this regard, threats may be particularly high for First Nations which are located in regions with high fire activities. Under climate change, fire-prone conditions are predicted to increase by 1.5 to 4 times before the end of the century across Canada. Currently, there are no comprehensive Canadian-wide fire exposure assessment for the WHI, nor for the quantification of the population that is exposed to different fire return intervals under current and future fire regimes. Using a number of new Canadian Forest Service (CFS) databases including regional fire exposure, fuel maps and climate projections, we assessed the current and future area of each type of WHI exposed to high fire return intervals, as well as the current and future population facing high fire return intervals in boreal Canada. Slightly more than 10%, 20% and 15% of the WUI, WInfI and WII are respectively currently experiencing short (< 250 yrs) fire return intervals under current climate conditions. These proportions would increase to 28%, 42% and 41% respectively after 2071 under the RCP 8.5 climate scenario. According to the 2011 census, about 12.3% of the Canadian population (4.1M) reside within the WUI with First Nations being overrepresented within the WUI. Currently, ca 5% of the Canadian population live in landscapes with short (< 250 yrs) fire return intervals, including >15% of First Nation population. These numbers would surge to >17% and >37% respectively in 2100 under RCP 8.5. Much higher fire exposure in the future within the WHI should trigger severe environmental, social and economic consequences. Our study should greatly help provinces, municipalities, agencies, industries and First Nations to know where the risks currently are and will be in the future and which mitigation measures are to be implemented.
Case Studies in natural hazards risk assessment of civil engineering systems
Impact of Flooding on Concrete Pavement Performance
Oluremi Oyediji, Susan Tighe
Mr. Oluremi Oyediji, University of Waterloo (Presenter) Dr. Susan Tighe, CPATT - University of Waterloo
Pavement infrastructures have become vulnerable to damage as they were not designed to withstand the aggressions of extreme weather events such as flooding, induced by climate change. In Ontario, flooding tops the list of climate change hazards having a consequential impact on pavement performance. Rigid pavements are recorded to provide resilience to flood hazard in literature but knowledge about its behaviour and response to flood impact is currently scarce. The objective of this study is to investigate the impact of flood hazards on the performance of concrete pavement examining a case study of Jointed Plain Concrete Pavement (JPCP) road classes in Ontario. A literature review of pavement flood impact and analysis of flood-induced distresses in concrete pavement is carried out. Subsequent to this, the Mechanistic-Empirical Pavement Design Guide (MEPDG) was employed to simulate JPCP performance under climate change using a conservative Representative Concentration Pathways (RCP) of 4.5W/m2. Only flood depth, duration and event cycles were used to define flood loading. Typical representative designs of JPCP collector and arterial road classes in the province were chosen and modelled. The result indicated lower damage ratios and loss of pavement life based on changes in faulting and International Roughness Index (IRI). Increases in flood frequency resulted in additional damages and loss of pavement performance and analysis showed that arterial pavement was more resilient to flood damage than collector pavements. Inference is that concrete pavements may significantly not have their life shortened at lower cycles of extreme precipitation. However, at higher frequencies of extreme precipitation, damage may increase and resilience to flood hazards in JPCP pavement altered.
Climate Change, Flooding, Concrete Pavement, Jointed Plain Concrete Pavement, Pavement Design
Wave Run-Up Contributions to Coastal Flood Hazards in New Brunswick
Enda Murphy, Jasmin Boisvert, Reid McLean, Vahid Pilechi, Julien Cousineau, Laxmi Sushama, Zijian Liang, Andrew Cornett
Mr. Enda Murphy, National Research Council of Canada Mr. Jasmin Boisvert, New Brunswick Department of Environment and Local Government Mr. Reid McLean, NBELG Dr. Vahid Pilechi, National Research Council of Canada Mr. Julien Cousineau, National Research Council, Canada Dr. Laxmi Sushama, McGill University Mr. Zijian Liang Dr. Andrew Cornett, National Research Council (Presenter)
New Brunswick’s coastal communities and civil engineering systems are vulnerable to flooding associated with tides, extreme storm surges and wave events. Coastal flood hazards and risks are projected to increase over time, as a consequence of urbanization and climate change effects, including relative sea level rise. New Brunswick’s Flood Risk Reduction Strategy (2014) and Climate Change Action Plan (2016) call for the renewal and expansion of the province’s existing set of coastal and inland flood hazard maps. The Coastal Flood Hazard Mapping project aims to develop new maps for approximately 2,270 linear kilometers of the New Brunswick coast.
Initial project tasks focused on establishing future extreme water levels for fourteen identified quasi-homogenous coastal flood hazard zones in New Brunswick. This excluded allowances for wave-related contributions to coastal flood hazards, such as wave run-up on the shore. A new, regional wave run-up study was conducted to address this data gap, and to provide representative extreme wave run-up heights for 614 zones along the New Brunswick coast. Zones were identified and classified according to extreme water level characteristics, wave exposure, shore type and gradient. The study involved statistical analyses of offshore wind and wave hindcast data, numerical wave transformation modelling to evaluate nearshore extreme wave conditions, and a systematic approach to calculating extreme wave run-up heights for each zone.
Nearshore extreme wave parameters and wave run-up height data generated by the study will be incorporated in a publicly accessible, web-based map application, which will inform coastal flood risk management and climate change adaptation efforts in New Brunswick. Further, exploratory research is underway to investigate the potential impacts of climate change on the nearshore extreme wave conditions in the region.
Cement and Concrete
Fresh state and Strength Properties of Geopolymer Pastes- Optimizing Activators and Supplementary Cementing Materials
Dhruv Sood, Khandaker Hossain
Mr. Dhruv Sood, Ryerson University (Presenter) Dr. Khandaker Hossain, Ryerson University
A geopolymer is a cement-free binder produced with the help of industrial waste products and alkaline reagents. This paper presents fresh-state and strength properties of geopolymer pastes by incorporating supplementary cementitious materials (SCMs) and powdered based activators with ambient curing. The performance of geopolymer pastes will be presented based on flow characteristics, initial/final setting time, heat of hydration and compressive strength compared to their Portland cement counterparts. The influence of SCMs types/dosages, activator types/dosages/combinations will be described to characterize optimized combination of SCMs and activators for the production of geopolymer based blended composites.
Keywords: supplementary cementitious materials, geopolymer, activators, pastes
Reinforced Concrete Pipe Design with Single Elliptical Steel Cage Reinforcement
Abdullah Ramadan, Moncef Nehdi, Sammy Wong, Abdul-Aziz Younis
Mr. Abdullah Ramadan (Presenter) Dr. Moncef Nehdi, Western University Mr. Sammy Wong, Con Cast Pipe Mr. Abdul-Aziz Younis
Reinforced Concrete Pipe Design with Single Elliptical Steel Cage Reinforcement
Abdullah S. Ramadan1, Abdul-Aziz Younis1, Lui Sammy Wong1,2 and Moncef L. Nehdi1
1 Department of Civil and Environmental Engineering, Western University, London, ON, Canada, N6A 5B9
2 Con Cast Pipe, 299 Brock Rd S, Guelph, ON N1H 6H9
Reinforced Concrete Pipe (RCP) relies primarily on its own structural strength rather than the bedding material around the pipe. It has been used in North America for over a century, with reliable performance. However, this industry has been experiencing declining market share for several years due to competition from the lightweight flexible pipe industry and tepid technological advancements. RCP strength is classified according to its design crack load using the Three-Edge Bearing Test (TEBT), which is defined as the load capacity without producing a 0.3 mm wide and 300 mm long crack. The test is destructive, applying a concentrated load along the crown of the pipe. The most common form of reinforcing RCP is the traditional double (inner and outer) steel-cage reinforcement. Current Canadian and American standards allow for the use of a single elliptical steel cage reinforcement as an alternative to the double cage. Single elliptical steel cage reinforcement can offer more effective design since the steel is more favourably positioned at the tensile face of the pipe. However, single elliptical steel cage reinforcement is not commonly used in the industry as its performance is not fully understood, coupled with manufacturing limitations of the elliptical steel cage. The goal of this study is to explore the structural performance of RCP reinforced with single elliptical steel cage reinforcement in comparison with traditional reinforcement. RCP specimens were tested under the TEBT, with the load deflection data collected using Linear Variable Displacement Transducers (LVDT) to further analyze the structural behavior. The study confirms that RCP with single elliptical steel cage reinforcement can provide significant cost reduction in both material and labour without compromising structural performance. The study also provides guidance for designing single elliptical steel reinforcement in RCP.
Keywords: Reinforced, Concrete, Pipe, Three-Edge Bearing Test, Design, Elliptical Reinforcement, Structure.
REVIEW OF MECHANICAL PROPERTIES AND DURABILITY OF ALKALI ACTIVATED SYSTEMS
Ahmed Abubakr, Ahmed Soliman
Mr. Ahmed Abubakr (Presenter) Dr. Ahmed Soliman, Concordia University
Alkali activated systems are getting popular in construction sector. This increases the demand to understand its performance. An overview of the advances in alkali activated materials (AAMs) produced through activating aluminosilicate raw materials is presented along with a discussion for advantages and disadvantages of this technology. Reaction mechanisms for different aluminosilicate sources with activators were analyzed in order to achieve a good understanding for final products nature, and parameters affecting the process. This was supported with fresh and hardened properties and microstructure analysis. Overall performance including fire resistance, reinforcement bars bond and bond between aggregate and matrix were presented for better understanding of the performance. Moreover, durability performance of AAMs was also discussed in a comparison to cement-based materials.
Keywords: review, alkali activated materials, mechanical properties.
Utilizing Industrial Wastewater in Production of Concrete : Experimental & Feasibility Study
Reem Ahmed, Mohamed Afifi
Mrs. Reem Ahmed, Concordia University Mr. Mohamed Afifi, McGill University (Presenter)
Concrete is the most widely used construction material in the world and is considered one of the largest water consuming industries as approximately 150 liters of water is required per cubic meter of concrete mixture. Recently, population explosion coupled with urbanization has raised the demand for water resulting in its scarcity making water a critical environmental issue that is limiting water supplies and water quality worldwide. On the other hand, with industrialization, the quantity of wastewater generated has soared up warranting appropriate measures for utilization and disposal.
This work addresses potential utilization of industrial wastewater in ordinary performance concrete. This study was conducted to investigate the possibility of saving water used in concrete mixtures and make use of produced wastewater domestically and industrially. Mixing water was utilized from wastewater from 7 different industrial plants: ceramic, marble, halva, jam and nestle factories. Non-treated effluents have been used as mixing water in concrete and mortar mixes utilized for preparing concrete & mortar cubes. Â Fresh concrete and Hardened concrete properties were assessed including slump, unit weight, compressive and flexural strength. The outcome uncovers that the utilization of wastewater from certain sources can produce mixes of comparable strength and durability when compared to control specimens created by tap water. Experimental work is backed up with a feasibility study, incorporating cost and resource savings to better judge the potential of the utilization of wastewater in concrete mixing.
Keywords: (Industrial Wastewater, Mixing Water, Mortar, Concrete)
A Decision-Support Tool for Assessing Climate Change Impacts on Design and Management of Urban Water Systems
Truong-Huy Nguyen, Van-Thanh-Van Nguyen
Mr. Truong-Huy Nguyen, McGill University (Presenter) Dr. Van-Thanh-Van Nguyen, McGill University
In recent years, climate change has been recognized as having a profound impact on the hydrologic cycle at various spatial and temporal scales. The global and regional climate models have been extensively used in many studies for assessing the potential impacts. However, due to current limitations on detailed physical modelling and computational capability, these models could only provide output scenarios at macro and meso scales and on a daily time step which are ineffective to inform decision-making at the micro (or local) scales. Thus, resolving the spatial and temporal scale issues are crucial, so that local decision makers can possibly evaluate what the likely climate change impacts are, such as maximum rainfalls, at the urban or local scales. Downscaling techniques in both space and time have thus been proposed to resolve the scale discrepancy issues. Of particular importance for urban drainage system design are those procedures dealing with the linkage of the large-scale climate variability to the local-scale historical observations of short-duration extreme rainfall processes over a given urban watershed. If this linkage could be established, then the projected change of climate conditions available at global or regional scales could be used to predict the resulting change of the local precipitations and the resulting urban runoff characteristics. In this paper, a decision-support tool (hereafter referred to as SMExRain) was proposed to address these issues. The tool has been developed to consolidate the weather extreme data and to help visualize the descriptive and predictive scenarios. This software is also capable of establishing the linkage between climate projections of climate change available at large-scale to local scales (i.e. to see smaller regional impacts of climate change) with and without empirical data. The feasibility and accuracy of the tool were evaluated based on the climate simulation outputs from 21 global climate models that have been downscaled by NASA to a regional 25-km scale for different representative concentration pathway scenarios and the observed extreme rainfall data over Ontario region, Canada.
A Fuzzy clustering approach to diagnosis of change in natural streamflow regime
Masoud Zaerpour, Shadi Hatami, Javad Sadri, Ali Nazemi
Mr. Masoud Zaerpour, Concordia Univeristy (Presenter) Mrs. Shadi Hatami, Concordia University Dr. Javad Sadri, Concordia University Dr. Ali Nazemi, Concordia University
Climate change have significantly changed natural streamflow regime in Canada. Understanding the regime shifts in natural streamflow is important in terms of effective water management and preparedness for facing potential threats to water, food and energy security in Canada. Conventional approaches to assess the change in natural flow regime consider one or more streamflow characteristics and apply statistical tests to extract the form and magnitude of change individually in the considered characteristics. Here we propose an alternative approach to diagnose the change in natural streamflow regime by characterizing the gradual shift in shape and variability around the long-term annual streamflow hydrographs, which inherently include multiple streamflow characteristics within. The proposed methodology is based on (1) considering a wide range of streamflow characteristics that together represent the long-term annual hydrographs and their associated natural variability; (2) clustering streamflow series based on these features into a set of physically-relevant streamflow classes; and (3) monitoring the gradual shift from one flow regime to others using a systematic approach. To test this framework, we consider the streamflow data from 106 natural Canadian streams during the common period of 1966 to 2010. Fuzzy clustering is used to classify the streamflow series during this period, in which all streamflow series are associated to all clusters with certain degrees of belongingness. We then focus on natural streams in the province of Quebec and measure the gradual departure in degrees of belongingness using moving windows and take this information as an indicator for regime shift in natural streamflow regime. Based on this methodology, we diagnose some significant changes in shape and variability of annual expected hydrograph in Quebec, which provides a holistic understanding of recent changes in natural streamflow regime throughout the province.
Evaluation of variability of precipitation and temperature extremes over Montreal region for present and future climates
Hoang Lam Nguyen, Truong-Huy Nguyen, Van-Thanh-Van Nguyen
Mr. Hoang Lam Nguyen (Presenter) Mr. Truong-Huy Nguyen, McGill University Dr. Van-Thanh-Van Nguyen, McGill University
Montreal is the largest city in the province of Quebec and has been known as a sensitive area to extreme weathers such as heavy storm rainfalls and heat waves. Hence, information on the spatial and temporal variations of these extreme weather events (e.g., precipitation and temperature extremes) for current and future climates is important for the planning and design of its urban infrastructures. This paper aims therefore at performing a detailed evaluation of the variability in time and in space of the daily annual maximum rainfalls and daily extreme temperatures over the Montreal region for the present and future climates using the data provided by two different sources: the Pacific Climate Impacts Consortium (PCIC) and the National Aeronautics Space Administration (NASA) Earth Exchange Global Daily Downscaled Projections (NEX-GDDP). More specifically, the evaluation was based on the climate simulation outputs from 10 different Global Climate Models (GCMs) downscaled (i) by PCIC to a regional 1/12-degree grid using the BCCAQ and BCSD methods; and (ii) by NASA to a regional 1/4-degree grid. For the present climates, historical data for the 1961-1990 period from observed weather stations located in the Montreal region were used for this evaluation. For the future climates, climate projections corresponding to the RCP 4.5 climate scenario for the 2006 – 2100 period were used. Results of this study have indicated that the outcomes of the downscaling from the Regional Climate Models (RCMs) given by PCIC are more precise than those given by NASA over the study area based on different statistical criteria.
Evolving trends of rain over precipitation in Canadian cold season during the late 20th century
Shadi Hatami, Ali Nazemi, Amirali Amir Jabbari
Mrs. Shadi Hatami, Concordia University (Presenter) Dr. Ali Nazemi, Concordia University Mr. Amirali Amir Jabbari, Concordia University
Cold season across the Canadian landmass is prolonged and includes regionally important hydrological processes, such as snowfall and snow accumulation, which provides a reliable freshwater resource during the warm season, in which the majority of environmental and socio-economic activities take place. Canada however is in the forefront of climate change effects and this implies less snow during the cold season. Understanding the historical evolution in characteristics of cold season precipitation during the recent past is therefore important for evaluating the extent of climate change and is insightful for provision of adaptive water management in the country. Here we study the evolution in ratio of rain over total precipitation (R/P) during the cold-season at 46 high-quality stations in Canada during the common period of 1961 to 2000. We examine the trend in consecutive 10-, 20- and 30-year episodes at each station to provide a notion of evolution in monotonic change in form of cold season precipitation across the country. A coefficient of variation for moving trend is defined to compare the evolution in trends between different Canadian regions. Our findings clearly illustrate consistent increments in significant trends in 30-year episodes in Atlantic and Central Canada as well as the West Coast, while more variability in evolutions of trends are observed for in 10 and 20 years. Further study shows that in majority of stations, the evolution in 30-year trends in R/P during the cold season coincides with the evolution of trend in mean temperature.
Incorporating Climate Change Considerations into Flood Mapping and Infrastructure Design in Newfoundland and Labrador
Joseph Daraio, Amir Ali Khan, Joel Finnis`
Dr. Joseph Daraio, Memorial University of Newfoundland (Presenter) Dr. Amir Ali Khan, Government of Newfoundland and Labrador Dr. Joel Finnis`, Memorial University of Newfoundland
Climate change is projected to bring warmer, wetter and stormier weather conditions across Newfoundland and Labrador (NL), with the most significant impacts expected for Labrador. Extreme precipitation and weather events are expected to increase in both frequency and intensity, and the degree of change will vary depending upon the local climate region. The potential for infrastructure damage and associated public safety risks, e.g. coastal erosion and property damage, will vary across the province. In March, 2017, the Government of NL (GNL) announced a plan to invest $3 billion dollars over 5 years through its infrastructure plan. Design of infrastructure requires the use of the statistics of extreme events to balance the cost of construction with estimates of the risk of failure. Recent climate trends and future climate projections show that past weather conditions can no longer be used to accurately predict the future and accurately assess risk. At present, climate change, or non-stationarity, is not consistently incorporated into infrastructure design in NL. Integrating climate change considerations into infrastructure and development decisions will ensure that new infrastructure investments are able to withstand the climate of the future. The GNL has a suite of world class data and resources available for this purpose, which includes recently updated (2018) regionally downscaled climate data for the province and updated Intesity-Duration-Frequency curves derived from these data. However, a number of issues has limited awareness and deployment of these resources, including the fact that key decision-makers and professionals are either unaware of the resources or lack in-house expertise to use them. Memorial University of Newfoundland has partnered with the GNL, Municipalities Newfoundland and Labrador (MNL), Professional Engineers and Geoscientists Newfoundland and Labrador (PEGNL), and Engineers Canada on a project funded by Natural Resources Canada to train professional engineers and planners on how to incorporate climate change considerations into infrastructure planning and design. We will discuss existing tools developed by the GNL, and how they have been used to date for flood mapping and infrastructure design, and plans to encourage and enhance the use of these tools. We will describe some of our recent efforts in knowledge transfer and training of professional engineers in the use of these tools. Finally, we discuss areas where further tool development is required, and identify some important knowledge gaps limiting our ability to incorporate climate change into infrastructure planning and design.
Stochastic Modeling of Daily Rainfall Process in the Context of Climate Change
Sarah El Outayek, Van-Thanh-Van Nguyen
Ms. Sarah El Outayek, McGill University (Presenter) Dr. Van-Thanh-Van Nguyen, McGill University
Information on the variations of extreme rainfall events in space and time is essential for the design and management of different water resources systems. However, it is difficult in practice to obtain this information simply based on the available historical precipitation records due to the random behavior of these phenomena, especially in the context of climate change. Hence, statistical and stochastic approaches have been commonly used for describing more accurately the spatio-temporal variability of the precipitation process. In particular, in the context of climate change the statistical approach such as the popular SDSM method has been often relied on the physically unrealistic assumption that the statistical model parameters remain the same for current and future climates. Consequently, the use of a stochastic approach should be considered as more suitable in order to overcome this limitation of statistical methods. The main objective of the present study is therefore to develop an original stochastic model to represent the daily precipitation process in the context of climate change. The proposed model (referred herein as MCME- Markov Chain Mixed Exponential) consists of two components: (i) the first component representing the occurrences of daily rainfalls based on the first-order Markov Chain; and (ii) the second component describing the daily rainfall intensities using the Mixed Exponential distribution. The MCME model can generate synthetic daily rainfall series having the same statistical properties of the observed data. A comparative study was then carried out to assess the performance of the MCME as compared to the popular LARS-WG stochastic model, using NCEP re-analysis data and observed daily precipitation data available in stations across the province of Quebec, Canada. Both models are calibrated and validated for the period between 1961 and 1990 in consideration of different climate change scenarios. Results of this assessment have indicated the feasibility, accuracy, and robustness of the proposed MCME model as compared to the LARS-WG model using a set of common graphical and numerical performance criteria.
Computational mechanics / Elasticity
DEAD LOAD DISTRIBUTION IN SKEW CONCRETE SLAB-ON-PRECAST CONCRETE I-GIRDER BRIDGES
Atefeh Iranmanesh, Khaled Sennah
Mrs. Atefeh Iranmanesh, Ryerson University (Presenter) Dr. Khaled Sennah, Ryerson University
In order to improve the bridge construction, using prefabricated elements has recently been more common in North America. Fabricating different bridge elements off-site has many benefits including higher material quality and durability, more efficiency in time and cost, increased safety of the work zone, less environmental impacts and decreased traffic disruptions. Moreover, many old bridges need rehabilitation, repair or replacement. Utilization of precast systems can significantly minimize the economic effects of a full-lane closure in large urban regions. The inconvenience caused to the traveling public can save time and tax payer’s money as well as enhancing the work zone safety. Currently, the Canadian Highway Bridge Design Code (CHBDC) specifies empirical equations for the moment and shear distribution factors in skew slab-on-girder bridges. However, there is no information available in the literature to verify the use of such equations for the design of the fully-precast CPCI girder bridges. Furthermore, the equations are limited to bridges with skew parameters less than a certain value specified in the code. However, skew bridges are necessary in some conditions such as crossing an obstacle or highway interchanges. The design of majority of skew bridges were not precise since they were designed as right bridges due to lack of researches. Since CHBDC load distribution factors were determined for general slab-on-girder bridges with limited value of skew parameters, a parametric study is required to investigate the applicability of these factors for precast bridge systems and bridges with higher values of skew parameters and without transverse intermediate diaphragms. In this study, a finite element modelling (FEM) was used to obtain load distribution factors for such bridges under self-weight and superimposed dead load and then correlate them with those available in CHBDC. Conclusions and recommendations for future research will be presented.
Flexural behavior of fiber reinforced lightweight self-consolidating concrete beams
Ali Ehsani Yeganeh, ali rashidian, Khandaker Hossain
Mr. Ali Ehsani Yeganeh (Presenter) Mr. ali rashidian Dr. Khandaker Hossain, Ryerson University
This paper describes flexural behavior of fiber reinforced lightweight self-consolidating concrete (FRLWSCC) beams made of slag aggregates in combination three different types of fibers such as: High-Density Poly Ethylene (HDPE), Crumb Rubber (CR) and Polyvinyl Alcohol (PVA). The performance of FRLWSCC beams compared to their lightweight self-consolidating concrete (LWSCC) counterparts is described based on load-deformation responses, stress-strain developments, crack characterization, failure modes, ductility and energy absorbing capacity. All beams have shown flexural failure the bending region. FRLWSCC flexural beams have shown higher ultimate flexural capacity, higher deflection, ductility and higher energy absorption capacity with development of more number of cracks with smaller crack width compared to their LWSCC counterparts.Â
Lateralâ€“torsional Buckling in Welded Girders: Prediction and Measurement of Residual Stresses
Daniel Unsworth, Robert Driver, Leijun Li
Mr. Daniel Unsworth (Presenter) Dr. Robert Driver, University of Alberta Dr. Leijun Li
Lateral-torsional buckling (LTB) is a potential mode of failure for steel beams involving a combination of weak-axis and torsional buckling resulting from strong-axis bending.
Canadian design standards CSA S6 and S16 specify checks that originated from the study of rolled steel beams to ensure they are designed to resist this failure mode. Although some research has been done to assess the applicability of these checks to welded sections, it was primarily conducted during the 1980s when controls on welding procedures were less stringent. Recent studies suggest that the Canadian standards overestimate the LTB capacity of welded beams; however, it is not clear that the residual stress distributions assumed are representative of girders in use today. For this reason, data from modern girders must be collected and examined.
The difference in LTB capacity between rolled and welded sections has been attributed to internal residual stresses. Because the distribution of these stresses differs considerably between welded and rolled beams, the buckling capacity of a welded beam could be substantially different from that of a rolled beam of identical cross-section.
The focus of this study is the measurement and analysis of residual stresses; another parallel study is carrying out large-scale buckling tests to determine girder LTB capacities experimentally. Consideration of residual stresses in conjunction with LTB capacities will allow for a better understanding of the effects of welding on LTB behaviour.
The testing program for this study comprises a comprehensive series of measurements on a set of reduced-scale lab test girders and a set of real bridge girders in the fabrication shop of a Steel Centre industry partner, Supreme Steel LP. Non-destructive ultrasonic testing (UT) is used to measure stresses in the latter, while the former are subjected to UT in conjunction with destructive sectioning tests to confirm the accuracy of the UT system. Past studies have shown UT to yield accurate results when used on welded steel structures; results agreed with those from x-ray diffraction, hole drilling and finite element modelling. The sectioning method has seen widespread use on welded steel sections and is widely considered to be an accurate baseline which non-destructive tests results can be compared to.
Knowledge of residual stress distributions and their impact on LTB behaviour will facilitate a broader evaluation of the current design procedure. Should the procedure prove unsafe, new provisions will be developed and proposed for Canadian design standards.
Structural stability of concrete spillway piers: development and application of 3D fiber elements including shear and warping deformations
DO VAN, Pierre Leger
Mr. DO VAN, École Polytechnique de Montréal (Presenter) Dr. Pierre Leger
Three-dimensional structural analysis methods for deep plain concrete spillway piers subjected 3D loads (P-Mx-My-Vx-Vy-T) can be divided into three categories: (i) the gravity method; (ii) 3D fiber elements; and (iii) 3D Finite Element method (FEM). The gravity method (GM) is used frequently in engineering practice. It is based on the Euler – Bernoulli beam theories with the assumption that cross sections remain plane after deformation. However, nonlinear normal and shear stress distributions induced by warping is not captured. Element warping can be captured by using 3D FEM using commercial software such as ABAQUS. Yet, 3D FEM requires significant resources and complex post-processing to compute classical engineering stability indicators such as (i) the sliding safety factor, (ii) the position of the force resultant, (iii) the cracked area, and (iv) the maximum compressive stresses. 3D fiber elements use conventional beam theory input parameters such as cross section area (A), moments of inertia (Ix, Iy, Ixy), shear sectional area (Ax, Ay, Axy) and torsional constants (J, G). Higher order beam theories leads to more precise results than the GM but with less complexity than 3D FEM in terms of engineering resources and result interpretation to take decision about the adequacy of stability indicators as compared to legal code requirements.
This paper presents a new higher order 3D fiber element using beam theory leading to a 18x18-stiffness matrix including shear and torsion warping. This element has two nodes and 9 degrees of freedom (DOFs) per node; 6 DOFs for normal displacements, and 2 additional DOFs for shear warping displacements in X and Y, and 1 DOF for torsional warping displacement (around Z). The element stiffness matrix is numerically integrated using a mixed isoparametric formulation: (i) the flexibility method is used for flexural and shear influence coefficients; (ii) the displacement method is used for torsional influence coefficients (Saint–Venant and bimoment). The element (fibers) cross sections along the beam are first discretized using 2D FEM. The element stiffness matrix is then computed from Gauss integration of cross sectional stiffness coefficients.
This new 3D fiber element element is implemented in a MATLAB code. Validations and verifications are performed using first a simple example of a plain concrete deep beam comparing simulation results to the exact solutions from elasticity theory. A more geometrically complex concrete deep pier of an existing spillway is then analyzed using ABAQUS (3D FEM) to validate the proposed fiber element model.
Assessment of the potentialities to develop raw earth as a sustainable building material
With a variety of forms, raw earth construction has long historical process in human civilization. As an ancient building material, it raises today a huge interest of architects and engineers considering its low ecological impact and its thermo-hygro-mechanical performances. Nevertheless, as far as raw earth is a heterogenous and unsaturated material, then considered as a multiphase soil (solid matrix, water and air) this material has a multi-physical property which still raises a complexity of proposing laboratory protocols to assess its standard performances. The aim of this paper is to sum up the principal knowledge about raw earth as building material. The complexity of its multi-physical behavior introduces one key parameter: the liquid degree of saturation. The moisture content mainly controls the thermo-hygro-hydro-mechanical behavior of raw earth and therefore its durability. But, in cold regions, the cyclic effects of water freezing and ice thawing on earthen houses cause an extreme moistening which represent a major risk of frost damage. This paper concludes with some theoretical approaches to model frost/thaw actions in an unsaturated soil.
Residual flexural strength of corroded reinforced concrete beams
Luaay Hussein, Lamya Amleh, Hesham Othman
Dr. Luaay Hussein, Ryerson University Dr. Lamya Amleh, Ryerson University (Presenter) Ms. Hesham Othman, Ryerson University
Corrosion of steel reinforcement in concrete has been regarded as a major problem in reinforced concrete structures, greatly shortening the service life and increases the maintenance cost of the structure. Thus, corrosion of steel reinforcement should be a great concern for materials and bridge engineers when designing new reinforced concrete structures and/or when evaluating the residual strength of existing reinforced concrete structures.
Several researchers studied experimentally and proposed numerical and analytical models to predict the flexural capacity of corroded reinforced concrete structures. However, some discrepancies between the analytical models and the actual experimental values have been observed. Moreover, all these models have their own limitations and drawbacks. The drawback is that the results are highly dependent on the specific structural considerations or depends on complicated bond models that require a lot of calculations. Therefore, it’s very important to propose a simple model that can be used by engineers to estimate the residual flexural strength of corroded reinforced concrete beams.
This paper presents a simple model that can be used to predict the residual flexural strength of reinforced concrete beams with varying degrees of reinforcement corrosion. The model accounts for the deterioration of bond strength at steel-concrete interface due to corrosion. The moment resistance method which is based on flexural analysis of reinforced concrete beams that considers the effect of bond deterioration was adopted. The results of the proposed model were validated by comparing the model with experimental results obtained by several researchers. The new proposed model in this study was able to successfully predict the residual flexural strength of corroded reinforced concrete beams.
Self-healing concrete: A review of recent research developments and existing research gaps
Sina Mahmoodi, Pedram Sadeghian
Mr. Sina Mahmoodi, Dalhousie University (Presenter) Dr. Pedram Sadeghian, Dalhousie University
Self-healing materials are defined as the materials that are able to partially or completely restore their original functionality after they have been damaged. In cementitious materials, this concept is referred to the capability of concrete to seal the cracks without any manual interventions after damage, accompanied by regaining of the mechanical properties, which results in a more durable and sustainable structure. In addition to the available literature which fully describes different methods of applying self-healing into cement-based materials and evaluates their efficiency, new approaches and novel techniques have been proposed for this purpose. This paper presents a brief review of both autogenous and autonomous mechanisms of self-healing, with an emphasize on the recent research advancements. Since the major concern regarding the application of autonomous self-healing in concrete structures is the additional cost caused by the healing agents, the improvement of autogenous self-healing which is an inherent performance of cementitious materials by providing a favorable condition for the process (e.g. HPFRCC) may pave the way towards construction industry. However, there are still a few aspects of self-healing concrete missing in the literature that inhibits this technology from being utilized in the construction. Therefore, a comprehensive section is proposed in this paper discussing the major gaps and outlooks in the field of self-healing concrete.
SIGNIFICANCE OF SERVICE LIFE BASED CONCRETE MIX DESIGN IN MARINE ENVIRONMENT
Tanvir Manzur, Md. Jihan Hasan, Bayezid Baten, Tafannum Torsha, Md. Fahim Azraf Khan, Khandaker Hossain
Dr. Tanvir Manzur, Bangladesh University of Engineering & Technology (Presenter) Mr. Md. Jihan Hasan, Department of Civil Engineering, Bangladesh University of Engineering & Technology (BUET) Mr. Bayezid Baten, Department of Civil Engineering, Bangladesh University of Engineering & Technology (BUET) Ms. Tafannum Torsha, Department of Civil Engineering, Bangladesh University of Engineering & Technology (BUET) Mr. Md. Fahim Azraf Khan, Department of Civil Engineering, Bangladesh University of Engineering & Technology (BUET) Dr. Khandaker Hossain, Ryerson University
Concrete mix design in many parts of the globe is still primarily based on strength requirement. One of the main reasons for strength focussed mix design is the relative simplicity and promptness of the strength measurement procedure. Moreover, concrete of higher strength are generally presumed to possess better durability. However, under severe exposure condition like marine environment, typical durability concept fails to provide required serviceability of a Reinforced Concrete (RC) structure. This structural hazard is usually significant in concrete structures of low to moderate strength, particularly evident in regions where durability is not a prime concern over strength, like Bangladesh. Â Any RC structure in marine environment is susceptible to chloride ingress and hence, requires impermeable concrete to hinder diffusion of chloride ions within it. The impermeability of concrete can be measured through chloride diffusion coefficient which eventually, has significant effect on corrosion initiation of reinforcement. The typical strength focussed mix design practices cannot ensure reduced diffusion coefficients since pore refinement is necessary to disconnect continuous pore system within concrete. Refinement of pores can be warranted through use of composite or blended cement that contains supplementary cementitious material like fly ash. Nevertheless, use of such composite cement could hamper the strength gain of concrete. As a result, use of Ordinary Portland Cement (OPC) is preferred over blended cements in most cases of strength based mix design. Considering all the aforementioned aspects, an effort has been undertaken in this study to investigate the probable service life of RC structures of some common concrete mixes targeted for low to moderate strength (in the range between 20.7 and 34.5 MPa) with a workable slump value (around 100 to 150 mm). Concrete mixes, considered in this study, were proportioned for both OPC and composite/blended cement in such a way to satisfy the strength ranges and slump criteria. Chloride diffusion coefficients of the mixes were obtained by non-steady state rapid migration test. Finally, a probabilistic approach was followed to ascertain probable service life considering concrete covers typically used in RC structures constructed in marine condition. It has been obvious from the study that factors affecting durability of concrete should be given utmost importance in order to achieve satisfactory service life. Only strength based mix design without a proper choice of cement type could result in extremely poor serviceability of RC structures under severe chloride exposure.
Study of Precast Concrete Crazing Due to Moist Curing
Lui Sammy Wong, James Cameron, Moncef Nehdi
Mr. Lui Sammy Wong, Con Cast Pipe (Presenter) Mr. James Cameron, Con Cast Pipe Dr. Moncef Nehdi, Western University
Precast concrete has been widely used around the world to accelerate the construction schedule. Better concrete quality is expected because fabrication is conducted under controlled environment. Accelerated curing method with high early cement adopted by many industry standards allows the precast manufacturer to maintain the factory efficiency without compromising the structural and durability performance. This paper reports on the surface crazing defects on the precast concrete products under four days moist curing. The crazing cracks has depth up to 2 mm deep resulted from the drying action from the fully saturated concrete product after extended moist curing period. A study was conducted understand the surface crazing defects on precast concrete made of self-consolidated concrete containing HE and GU cement. The effects of various curing regimes including air dry, immersion using portable water, water bath and burlap and various relative humidity during drying process after the concrete is removed from the moisture curing. The corresponding mechanical properties are also reported. The study concluded that the rate of drying and the type of cement impacts the final surface condition and contributes to the concrete crazing defect observed on the precast concrete product.
Construction education and Global construction issues
A Statistical Analysis of the Effectiveness of Using 3D Models in Teaching Quantity Surveying Techniques
Namhun Lee, Seong-Jin Kim, Krishna Kisi
Dr. Namhun Lee Dr. Seong-Jin Kim Dr. Krishna Kisi, Central Connecticut State University (Presenter)
The AEC industry is shifting from 2D CAD to 3D model use. In the coming years, every design project will be modeled using BIM. Nonetheless, BIM is merely used as a tool to produce 2D drawing sets from 3D models. BIM for construction is to promote collaboration through consistent information models with greater standardization. BIM will help project managers not only streamline the design and construction processes but also add new capabilities to better serve their clients. Quantity takeoff is one of the most critical subjects in construction engineering and management (CEM) education. To perform a detailed quantity takeoff, it is required to review a set of drawings, create mental images of building elements, and calculate quantities of building materials. It is often exasperating for students to convert the 2D design information into 3D mentally. Using 3D models designated as LOD 300 or higher supports the quantity takeoff process since they address building element geometry. The objective of this study is to investigate the effectiveness of using 3D models to teach quantity surveying techniques in education settings. To accomplish this objective, a pilot study was carried out. Students’ performance data were collected from four different sections of a construction quantity takeoff course. To analyze the data statistically, an independent sample t-test was used. After analyzing the results, some pedagogical strategies for effective use of 3D models to teach quantity surveying techniques were discussed. The results of this study present a stepping stone towards the future of CEM education.
Construction industry Professionals' Perspective Towards Communication Technology and Education
Krishna Kisi, Namhun Lee, Kishor Shrestha, Santosh Bhandari
Dr. Krishna Kisi, Central Connecticut State University (Presenter) Dr. Namhun Lee Dr. Kishor Shrestha, Montana Technological University Mr. Santosh Bhandari
The advancement of Communications Technology (CT) has benefitted many industries. Since the construction industry has used CT to increase efficiency and performance, this paper focuses on determining the level of usage, proficiency, and perception towards incorporating CT in the construction industry in Missouri and Kansas states. A survey was conducted among 36 construction-related firms. This study found a positive acceleration in the use of CT in the construction industry. Results show that communications were less preferred via social media or text to exchange information related to their business. Nonetheless, the respondents believe that social media could be used for public relation and advertisement. The results show that industry professionals want university students to enroll more than three credit hours of construction-related courses such as estimating and designing. This study also investigated how industry professionals see their new hires in their companies in terms of fresh graduates’ CT skills. The results found out that about fifty percent responded they were semi-skilled. Based on these findings, the authors of this paper recommend that students need to learn more CT skills and enroll more CT-related courses. The study recommends students considering classes that enable them to collaborate more and interact.
Construction Software Technology Education at California Polytechnic State University – San Luis Obispo
Jason Hailer, Andrew Kline, John Cribbs
Mr. Jason Hailer, Cal Poly - SLO (Presenter) Mr. Andrew Kline, Cal Poly - SLO Dr. John Cribbs, Wentworth Institute of Technology
This paper discusses the challenges, accomplishments and overall process of teaching Building Information Modeling (BIM) at a major university. The focus of the California Polytechnic State University – San Luis Obispo (Cal Poly-SLO) Construction Management Department’s Technology class was to introduce and utilize relevant technologies currently deployed within the Architecture, Engineering and Construction (AEC) industry. Industry partners from the Cal Poly-SLO Construction Management Advisory Council (CMAC) participated in a survey and/or an interview to understand industry expectations in regards to technology readiness from a future graduate. Based on these results and the support of the departments Technology Advisory Committee (CTAC), the course implemented ten of the top software platforms into the class. Following each quarter course session, students participate in a survey regarding their understanding of the software tools and whether they feel confident deploying those tools in their professional careers. This paper introduces the software platforms introduced in the course, the lab-based exercises the students complete in order to prepare graduates to be successful entering the workforce and the results of the industry and student surveys/interviews. Further survey/interview data will be collected to determine if the construction technology skill-set development fulfills the dual goals of preparing students as well as graduating 1st-year AEC professionals capable of utilizing these software platforms effectively and efficiently. UPDATE: Due to the reviewers comments upon abstract acceptance, the paper was expanded to include a comparison of BIM curriculum deployment at a similar institution.
Low-cost Smart Productivity Tracking Model For Earthmoving Operations
Ashraf Salem, Osama Moselhi
Dr. Ashraf Salem, Concordia University (Presenter) Dr. Osama Moselhi, Concordia University, BCEE
Ashraf Salem and Osama Moselhi
Construction Automation Laboratory
Department of Building, Civil and Environmental Engineering
Gina Cody School of Engineering and Computer Science
Concordia University, Montreal, Quebec, Canada
This paper introduces a model for automated monitoring and control of productivity in earthmoving operations. The model makes use of advancements in wireless sensing networks, Internet of Things (IoT), and artificial intelligence. It consists of two modules; the first is a low-cost open-source remote sensing data acquisition module for collecting data throughout earthmoving operations. The collected data is sent to a cloud-based MySQL database, in which the second module is designed to (1) measure actual productivity in near-real-time, (2) detect the location and condition of hauling roads and (3) monitoring and reporting driving conditions over these roads via short email messages. The work encompassed field and scaled laboratory experiments in the development and validation processes of the developed model. The laboratory experiments utilized 1:24 scaled loader and dumping truck to simulate loading, hauling and dumping operations. The truck was instrumented with the microcontroller equipped with accelerometer, GPS module, load cell and soil water content sensor. Fifteen simulated earthmoving cycles were conducted using the scaled equipment. The field work was carried out in the city of Saint-Laurent, Montreal, Canada using a passenger vehicle to mimic the hauling truck operational modes. Fifteen Field simulated earthmoving cycles were performed. The data collected from the lab experiments and field work was used as input for the developed model. The results will be presented, highlighting the accuracy of the developed model in recognition of the status of the hauling truck, traveled road condition and in the estimated duration of the simulated earthmoving cycles.
Policy and Performance Evaluation of Cladding Systems with Large Window Areas in Tall Residential Buildings
Patrick Marquis, Arash Shahi, Brenda McCabe, Paul De Berardis, Michael de Lint
Mr. Patrick Marquis, University of Toronto Dr. Arash Shahi, University of Toronto (Presenter) Dr. Brenda McCabe, University of Toronto Mr. Paul De Berardis, Residential Construction Council of Ontario Mr. Michael de Lint, Residential Construction Council of Ontario
As governing bodies attempt to reach ambitious GHG goals, urban development is being increasingly regulated to improve energy efficiency and ensure long-term sustainability of the built infrastructure. With the growing popularity of tall buildings in dense urban centres and the demands for net-zero energy buildings, the Window-to-Wall Ratio (WWR) of these buildings is seen as a low-hanging fruit to help reduce energy loads, leading to stricter prescriptive WWR regulations. In this paper, a critical review of the WWR regulations for tall residential buildings in the city of Toronto, with one of the highest urban development rates in North America, is presented, which included the examination of 283 tall towers. Instead of relying solely on WWR, this research introduces the effective WWR (EWWR) as an additional occupant-focused measure of the window area of tall buildings, which considers the occupant’s living experience in tall towers. Finally, alternative passive solutions are presented, which can provide a balance between energy performance and livability in tall towers without reducing the WWR.
Revenir aux fondements du Lean dans l'usage du PDVSM en construction
Jean-François Côté, Sylvie Doré, Forgues Daniel
Mr. Jean-François Côté, ÉTS - École de technologie supérieure [nid:3192] (Presenter) Ms. Sylvie Doré, L'École de technologie supérieure (ÉTS) Dr. Forgues Daniel, Ecole de technologie supérieure
La construction a évolué, entre autres, grâce à la transposition du Lean manufacturing en Lean Construction et de la CAO. Malgré tout, les résultats escomptés n’ont pas été atteints : l’application du Lean [construction] reste subjective, la modélisation, périphérique et lourde, l’ingénierie, séquentielle, la gestion de projet, traditionnelle. Dans l’industrie manufacturière, il est courant de gérer le cycle de vie des maquettes numériques intégrées, paramétriques et contextuelles créées en CAO, en axant le processus sur la fluidité des informations constituant le bien à produire, le tout en ingénierie simultanée et non en fonction des tâches et des disciplines. Cette fluidité peut être visualisée avec l’outil Product Development Value Stream Mapping (PDVSM).
Le PDVSM a contribué largement à l’identification des sources de gaspillage en conception dans le domaine manufacturier. Toutefois, l’usage de cet outil peut être problématique en conception. Une tendance est de compartimenter les processus par niveau de détails ou par discipline, comme en production manufacturière. En construction, un bâtiment est une combinaison de disciplines et de documents. Un processus compartimenté, manquant de détails, masque un potentiel manque de coordination multidocumentaire et multidisciplinaire.
Le processus étudié est le quatrième bâtiment d’un complexe de construction, où la CAO a été intégrée au fur et à mesure de l’évolution de chaque bâtiment. Le processus a été visualisé par cartographie à l’aide du PDVSM, à partir de données récoltées par méthode ethnographique. Ce processus non simplifié, global, à haut niveau de détails, multidocumentaire et multidisciplinaire, expose et valide les sources potentielles de gaspillage.
Les résultats de cette recherche exposent une généralisation du manque de coordination multidocumentaire et multidisciplinaire, malgré le fait que d’immenses efforts ont été faits pour améliorer les processus. L’intégration de la CAO est limitée majoritairement aux techniciens, se traduisant par un risque généralisé de surproduction d’informations, de cycles itératifs à non-valeur ajoutée et de potentielles erreurs de conception. Des processus compartimentés, à faible niveau de détails, n’auraient pas pu exposer ces gaspillages. Seule l’expérience du personnel technique aurait pu y parvenir.
Le PDVSM utilisé selon une approche globale et à haut niveau de détails permettrait de refondre adéquatement les processus de conception selon un flux d’informations fluide et logique, axé sur la modélisation d’une maquette numérique intégrée, contextuelle et paramétrique, utilisée par tous, selon les principes de l’ingénierie simultanée.
Comparison among Project Delivery Methods for Scattered Rehabilitation Projects
Ehab Kamarah, Mohamed Attalla, Tarek Hegazy
Mr. Ehab Kamarah, York University Dr. Mohamed Attalla, University of Illinois (Presenter) Dr. Tarek Hegazy, University of Waterloo
Public-Sector organizations such as School Boards and Universities administer a large number of facilities that involve thousands of assets at various ages and require extensive yearly rehabilitation and capital renewal programs. Since these rehabilitation programs involve hundreds of small repetitive works that are scattered in many locations, organizations are struggling to deliver these programs on time and on budget, to keep their facilities operational, despite suffering from billions of dollars in rehabilitation backlog. While significant efforts in the literature have been dedicated to decide the components to include in rehabilitation projects, fewer efforts address the delivery phases of such projects. Existing project management systems exhibit serious drawbacks, not only in considering the scattered multi-location nature of the work, but also in scheduling and tracking the progress of the large number of small subprojects involved. Moreover, existing delivery methods consider each subproject separately and deprive owner organizations from benefiting from repetition to achieve significant cost savings. In an effort to improve the project delivery practices of infrastructure rehabilitation projects, this paper investigates the most suitable project delivery method that suits scattered repetitive projects. The paper highlights the drawbacks of common delivery methods and suggests specific requirements for an efficient project delivery method for scattered rehabilitation projects. The guidelines suggested in the paper supports decision makers at public organizations to optimize the contractual and execution environments of the costly and very constrained infrastructure rehabilitation programs
COMPETITIVE FINITE ELEMENT ANALYSIS (ANSYS) FOR THE USE OF ICE & FROZEN SILT AS A SUPPORTING STRUCTURAL MATERIAL, AN ALTERNATIVE TO THE TRADITIONAL CRAWLER CRANE MAT MATERIAL (S355, G40.21 & COASTAL DOUGLAS-FIR)
Ghulam Muhammad Ali, Mohamed Al-Hussein, Ahmed Bouferguene, Joe Kosa
Mr. Ghulam Muhammad Ali, University of Alberta (Presenter) Dr. Mohamed Al-Hussein, University of Alberta Mr. Ahmed Bouferguene, University of Alberta Mr. Joe Kosa, NCSG Crane and Heavy Haul Services
The construction industry is moving towards modular construction paradigm with the integration of heavy crane usage. The unsubtle burning of resources creates an inevitable psychological push for the search for new construction methods and materials. The concept of ice as a supporting structure is not new. For instance, a British-led classified project during the Second World War, Project Habakkuk, sought to develop an aircraft carrier composed of ice. Canadian workers built a prototype at Patricia Lake, Alberta. This project was abandoned due to lack of innovation. This showed the inspiring future of ice as a supporting structure in the cold region, especially the north-western part of Canada. On the other hand, the soil mixed with water, the resulting frozen soil/silt has strong mechanical linear and non-linear figures competing with timber (Coastal Douglas-Fir). The idea behind this research contribution is to investigate the competitive analysis for the use of ice or frozen silt as a crane mat to support heavy lifting and hauling. Finite Element Analysis is performed to simulate the crawler crane loading. At the same time, the impact of loading on the crane mat under the crawler crane track is monitored using ANSYS (FEA platform). Five matting material (S355, G40.21, Coastal Douglas-Fir, ice & frozen silt) are investigated using five linear and one non-linear mechanical properties under identical boundary conditions. The required mat surface temperature for frozen silt is considered -10 Â°C based on the competitive mechanical properties for its practical usage and Finite element simulation. The graphical outcome in the form of normal stresses and ground deflection along the crane superstructure slew provides a perceptual mapping for the utilization of ice or frozen slit against traditional competitors (steel/wood). The resulted graphical representation shows that the compressive stresses under the mat are non-uniform in nature. Moreover, the findings are favorable for the use of frozen silt as crane support. The behavior of frozen silt is at par with Timber Mat (Coastal Douglas-fir). This similarity builds the confidence for the preparation and usage of frozen silt mat. The conclusions from these simulations will provide a foundation for the estimation of the freezing process in conjunction with ground freezing techniques. The findings can be used later to build a baseline for the cost estimation for the alternative crane matting solution in the form of capital, operational and opportunity cost for this novel approach instead of timber mat ground support.
Construction Labor Productivity Benchmarking: A Comparison Between On-Site Construction and Prefabrication
Construction labor productivity has been declining over the past sixty years which has caused a decline in overall construction productivity. The traditional way of managing construction project and its delivery have evolved into an inherently inefficient and adversarial process. There was always a need to improve how the way construction elements are constructed and delivered to the job site. Lean Construction, an innovative approach was introduced to the construction sector in the last century to improve construction productivity through maximizing value and eliminating waste. Prefabrication is a process of assembling building components in a remote location using a production line in a controlled environment and delivering the parts to the construction site for installation. There have been numerous studies comparing prefabricating construction labor productivity to on-site labor productivity. These comparative studies were conducted at industrial or project levels only but not at the task level. Therefore, the results lack the comparative data analysis which identifies the direct, indirect and idle times which workers spent in both environments. This research is to address this gap of knowledge by conducting quantitative statistical analysis of construction labor productivity investigating the effect of prefabrication environment on construction labor productivity by comparing prefabricating wall panels to on-site wall panels installation.
The study will provide a better understanding of the factors affecting labor productivity in both environments. The task level comparative analysis presented in this research will inform the construction firms and contractors with the data time allocated by workers in prefabrication and on-site construction, which will assist them to improve the labor productivity and consequently to improve the construction productivity by identifying the deficiency in the construction labor time.
Crack Analysis of Electrically Conductive Heated Pavement Systems through Finite Element Modeling
Sajed Sadati, Adel Rezaei-Tarahomi, Kristen Cetin, Halil Ceylan, Sunghwan Kim
Mr. Sajed Sadati, Iowa State University Mr. Adel Rezaei-Tarahomi, Iowa State University Dr. Kristen Cetin, Iowa State University (Presenter) Dr. Halil Ceylan, Iowa State University Dr. Sunghwan Kim, Iowa State University
The construction of electrically conductive heated pavement systems includes embedding electrodes in the conductive layer of the concrete. These electrodes are necessary for developing electric current in the conductive layer of the pavement system and ultimately for heat generation. However, the impact of the location and properties of the electrodes should be studied to evaluate the structural performance of the pavement under the expected loading, as well as methods to help to prevent the occurrence of cracks. In this study, two finite element models of electrically conductive heated pavement system are developed, including a model of the pavement system i) with electrodes, and ii) without electrodes, each simulating cracking in the same location. The structural response of these two systems under specific sets of realistic loading conditions which simulate traffic loads are then compared. The difference between the results of the two models shows the impact of the electrodes on the structural performance of the system. The outcomes of this study provides guidance regarding the construction process of the electrically conductive heated pavement systems, and recommendations to help minimize the potential for cracking due to the existence of electrodes. Â
Developing a Constructability Implementation Framework for Transportation Projects
Adi Al-Smadi, Dan Tran
Mr. Adi Al-Smadi, The University of Kansas Dr. Dan Tran , University of Kansas (Presenter)
A constructability review process (CRP) is a systematic approach for reducing design errors, disputes and claims, and cost and schedule escalations throughout the project development process. Current approaches to CRP vary among state departments of transportation (DOTs). Some state DOTs, such as California, Indiana, and Washington DOTs, utilize formal constructability approaches that utilize special teams, resources, and lessons learned while implementing constructability. Other state DOTs employ informal approaches that incorporate partial constructability considerations as part of their processes. Consistent approaches for selecting, evaluating, and implementing constructability reviews across state DOTs is essential to reduce cost and schedule overruns. This study introduces a decision-making framework for constructability implementation to assist state DOTs effectively and efficiently perform constructability reviews for their highway projects. The framework composes of three main levels: (1) Project information level- using a combination of related factors to select a CRP for each project, (2) Constructability processing level- incorporating probabilistic assessment of constructability related issues to evaluate their impact on the anticipated project cost, time, and risks, and (3) Implementation level- developing a guideline to assess agencies in implementing the framework. To develop the framework, the authors collect and analyze data related to current constructability programs from 50 state DOTs in the U.S. The outcome of this study will help decision makers determine the most appropriate means to incorporate construction knowledge into CRPs.
Implementation of Bridge Bundling Delivery Method: the view from the field
Mamdouh Mohamed, Dan Tran
Mr. Mamdouh Mohamed, University of Kansas (Presenter) Dr. Dan Tran , University of Kansas
As many states continue to see an increase in the number of bridges needing attention, awarding two or more bridge projects into a single contract can offer potential savings in resources and time. In addition, this approach is directly benefiting expedient improvements to the aging infrastructure nationwide. Thus, state departments of transportation (DOTs) and local bridge agencies are increasingly using a bridge bundling approach to benefit from the economies of scale and enhance the overall program performance.In essence, bridge bundling incorporates more than one bridge construction/replacement or maintenance/rehabilitation project into one program.
This study explores the current practices of implementing bridge bundling methodology with different types of project delivery and procurement methods. To obtain this goal, data were collected from a literature review and case study projects. Four bridge bundling programs from Missouri DOT, Pennsylvania DOT, Delaware DOT, and Ohio DOT were examined. The research results showed that, compared to single project delivery, bridge bundling offers several advantages such as (1) improving the performance measures of the highway infrastructure asset system,(2) reducing the number of bridges in a poor condition, (3) providing cost saving and improve project schedule, and (4) early starting construction. Further, bridge bundling reduces the burden on agency staff by preparing procurement for one contract, reducing management oversight, and coordinating with one contractor only. Furthermore, this study provides eight typical procedures that bridge agencies can follow to create a bridge bundle. These procedures begin with identifying bridge inventory and performance goals and end with creating a construction bundle.
Public-Private Partnerships (P3s) in the US, Observed Obstacles to its Adoption, and Potential Solutions to Overcome the Challenges
Lameck Onsarigo, Simon Adamtey
Dr. Lameck Onsarigo, Kent State University (Presenter) Dr. Simon Adamtey, Kent State University
A well-developed infrastructure system is crucial to the health of a nation’s economy. The ASCE’s 2017 Infrastructure Report Card rated America’s infrastructure at a D+ and highlighted the dire need for infrastructure investment in the US. According to the report card, the 10-year investment gap that must be bridged in order to achieve an infrastructure system fit for the 21st century is close to $2.0 trillion. The inability of government funding to bridge this investment gap, explains the recent growth in the market for public-private partnerships (P3s) in the US. P3s refer to contractual cooperation between public agencies and private entities to design, construct, finance, operate and maintain a facility or infrastructure. While other nations including the UK, Canada and Australia have highly utilized private financing and expert input to improve and update their infrastructure, the US is behind the curve when it comes to adoption of P3s. This paper presents result of an extensive literature review on P3s in the US and interviews with experts in the industry. The paper addresses the suitability of P3s in supplementing the conventional government efforts in rebuilding the US infrastructure. The paper also discusses the main obstacles to adoption and successful implementation of P3s in the US and proposes ways to overcome the obstacles and successfully execute a P3s
When fast track construction leads to affordable high end housing.
Serge Parent, John Clark
Mr. Serge Parent, Consultants SteelSSALG (Presenter) Mr. John Clark, Niche Development
The most common types of structural framing systems used in North America for residential construction remains to these days wood framing, cast in place concrete, light gauge steel or steel framed buildings. Although each type offers its advantage and inconvenient, when it comes to reach high speed of construction in congested urban job sites, a balanced use of prefabricated components remains the key to access high end quality buildings at lower cost. Belgravia Square located in Edmonton’s Belgravia neighborhood is presented in this paper as an example of hybrid construction using steel frame combined with multiple precast components. Each of these precast components were chosen to either accelerate construction or to address a site specific construction constraint for this 4 storey, 60,000 square foot building. Due to vertical excavation cut needed almost on property line, precast foundations walls were installed to maximize the building footprint. Precast stair cases, elevator shaft and hollowcore floor panels were installed by the same erector in charge of putting the building in place as it was going up in height. In a constant effort to adapt the building to its natural environment and to promote an eco-friendly construction, an innovative tree pot L-shape precast box was used to preserve all existing century old trees located on the property line. While preserving all trees, this underground precast component was instrumental in maintaining all parking stalls. The fast track construction from detailing to erection, and the economics of this 68 condominium unit building erected in less than 6 weeks is described and compared to other conventional construction methods. This case study serves to demonstrate that short construction time in complicated urban site is no excuse to affordable and luxury multi-unit housing.
Contaminated Sites I
CONTAMINANT TRANSPORT MODELLING FOR RISK ASSESMENT
Contaminant transport refers to the spreading of the contaminants from the source of contamination to the drinking water supplies. Nevertheless, the groundwater contaminant transport modelling is a rarity as part of the risk assessment process. Detailed calculations, in-depth scientific and technical knowledge is required in addition to understanding of complex hydrogeological settings. The development of commercial softwares has reduced the time and effort to predict the groundwater transport with varying hydrogeological conditions. Nevertheless, it remains imperative to understand the mathematical relations and definitions with respect to the constant and variable input parameters leading to 3D and 2D models. (A) This research is an attempt to gather the various numerical equations typically used for modeling the contaminant concentration and transportation within the groundwater system.(B) A workflow example for computer based modelling using GMS (Ground Water Modeling) software using the MODFLOW and MT3DMS simulation programs.
Discovery of the New Oil-Degrading Bacteria with Biosurfactant Production Ability from Oily Tailings Ponds Waste, Oil-Polluted Soil, and Light and Heavy Crude Oils for Remediation of Crude Oil in Water
Nayereh Saborimanesh, Mohammad Rahimi, Catherine Mulligan
Dr. Nayereh Saborimanesh Mr. Mohammad Rahimi (Presenter) Dr. Catherine Mulligan, Concordia University
Contamination of water and soil with crude oil and petroleum compounds frequently occurs. Removal of oil contamination is often not economically feasible by traditional remediation techniques. Therefore, the development of effective, fast, and bio-based remediation methods that can lessen the damaging effects of oil contamination and lower treatment costs are of great importance. Numerous oil-degrading bacteria with biosurfactant production ability have been isolated from oil-related environments. However, less attention has been given to the application of these compounds in the oil-related activities. For this purpose, in this study, new oil-degrading bacteria with the biosurfactant (BS) production ability were discovered with excellent properties for oil bioremediation application. Several oil-degrading bacteria with biosurfactant production ability were discovered from samples including oily tailings pond waste, petroleum-contaminated soil, and light and heavy crude oils by using the enrichment culture technique with Bushnell-Hass media. The biodegradation tests were conducted in flasks containing mineral salt medium (350 ml, pH, 7; salinity of 30 ppt) and crude oil as the only carbon source (2 mL) to determine the contribution of oil-degrading bacteria in the crude oil biodegradation. Flasks were incubated on an orbital shaker (Thermolyne AROS) at 120 rpm and temperature (26 ± 1°C) for five weeks. Moreover, the produced biosurfactants physicochemical properties, quality, and quantity were determined using surface tension (ST) and oil-displacement methods. The level of oil degradation at different periods of biodegradation was monitored weekly by analysis of the remaining of total petroleum hydrocarbons using a gas chromatograph (GC-FID). A total of five oil-degrading bacteria were discovered from oily tailings ponds waste (1 species), petroleum-contaminated soil (two species), light crude oil (one species) and heavy crude oil (one species). All species showed biosurfactant production ability. The lowest surface tensions of supernatants were between 55 mN/m to 40 mN/m. The minimum ST belonged to the BS produced by species discovered from oily tailings pond waste (40 mN/m). Moreover, an average crude oil biodegradation of 70% was obtained with all the isolated bacteria from samples during the five weeks of biodegradation period. This study confirmed the fast and effective biodegradation of crude oil by the isolated bacteria with the biosurfactant production as the main mechanism of oil uptake.
POTENTIAL HYBRIDIZATION OF BIOREMEDIATION AND DESALINATION: A PRELIMINARY STUDY FOR SALT-TOLERANT BACTERIA
Wonjae Chang, Aslan Hwanhwi Lee, Jihun Kim
Dr. Wonjae Chang, University of Saskatchewan (Presenter) Dr. Aslan Hwanhwi Lee, University of Saskatchewan Mr. Jihun Kim, University Of Saskatchewan
Microbes and minerals interact in nature. The compatibility of microbial metabolisms with reactive mineral treatments may allow useful environmental processes to be further engineered for the removal of multiple contaminants. We have focused on hybridizing bioremediation and desalination processes to remove hydrocarbons, sodium and chloride from contaminated oilfield produced water, oilfield wastes and impacted soils and groundwater. The main remedial agents in this combined remediation strategy are native salt-tolerant hydrocarbon-degrading bacteria (hydrocarbon biodegradation) and functionalized mineral amendments (desalination). Some indigenous hydrocarbon degraders in oilfield soils are halotolerant and can be metabolically active in both the absence and presence of salts (NaCl), unlike halophiles, which require salt to grow. These halotolerant populations are potentially beneficial when combining bioremediation and desalination, as the salt concentration varies. Our preliminary live cell image analysis indicated the significant survival of representative salt-tolerant hydrocarbon degraders subjected to over 5% salinity stresses in the presence of hydrocarbons, which potentially suggests the feasibility of developing hybrid bioremediation and desalination strategies for oilfield site remediation. Our study has continuously advanced to exploring the compatibility of the characterized salt-tolerant hydrocarbon-degraders (bioremediation agent) with the positively and negatively charged minerals for desalination.
Contaminated Sites II
Assessment of Groundwater below a Contaminated Soil Landfill Including Modeling of Vadose Zone
Mahad Baawain, Ahmed Sana, Yahia Mohamedzein
Dr. Mahad Baawain, Sultan Qaboos University (Presenter) Dr. Ahmed Sana, Sultan Qaboos University Dr. Yahia Mohamedzein, Sultan Qaboos University
This study aims at assessing the groundwater contamination underneath a waste yard that receives oily contaminated soil (CS). So, comprehensive analysis was conducted for the groundwater samples from upstream and downstream of the CS site. Furthermore, the study modeled the solute (hydrocarbons) transport in the unsaturated zone (i.e. the zone between ground surface and groundwater table). The geotechnical investigation consisted of drilling and installation of two 50 m deep groundwater monitoring wells (one well located 500 m upstream and another well located 300 m downstream of the dumping site). The groundwater was encountered at a depth of 42.5 m in borehole 1 and 43 m in borehole 2. The wells were developed using a pumping rate of 2.8 m3/hr. After pumping, the water level in the wells was 24.5 to 24.8 m below the top of the casing.
According to the collected samples, the groundwater underneath CS site is brackish water (salinity > 40 mS/cm and TDS > 24,000 mg/L) with relatively neutral pH (7 to 7.4). Hence, it cannot be used for potable uses without significant desalination process. Both samples taken from upstream and downstream wells show high hardness (~6,000 mg/L as CaCO3) and relatively low alkalinity (50 mg/L - 80 mg/L as CaCO3). The sulphate content is very high (>2,700 mg/L). The results did not show any heavy metal content. Furthermore, the amount of the different types of hydrocarbons in the groundwater samples were below detection limits of 0.01 mg/L).
A well-known model for flow and solute transport in variably saturated porous media has been applied to study the infiltration of water and solute (dissolved hydrocarbons) transport. The computations were done using in-situ values of percolation rates and laboratory measured permeability values of compacted soils. The concentration of solute (dissolved hydrocarbons) was computed for a period of two years over a depth of 2 m below ground. For the highest percolation rate observed at dumping site, the concentration of solute 2 m below the ground after two years was computed to be 0.0007 mg/cm3 (i.e. 0.00007%) approximately. Therefore, the chances of the oil contamination reaching the water table are remote. Moreover, the migration of contaminants can be reduced further by compacting the soil underneath the CS sites as evident from the modeling results by using lab permeability of compacted soil.
Mitigation of underwater sound levels with bubble curtains during resurfacing operations of the piers at the port of Gros-Cacouna
Djibril Sy, Vincent Le Borgne, Ã‰nias Antoine, Shayn Levoy, Mario Paris
Mr. Djibril Sy, GKM Consultants (Presenter) Mr. Vincent Le Borgne, GKM Consultants Mr. Énias Antoine, GKM Consultants Mr. Shayn Levoy, Canadian Pond Mr. Mario Paris, Canadian Pond
Protection of marine mammals in the vicinity of human activities has been a growing concern in Canada over the past decade. Construction activities, oil and gas exploitation, container boats can all have direct impacts on marine mammals such as beluga whales and dolphins. As part of maintenance of the installations of the port of Gros-Cacouna, Quebec, the sidewalls of the piers were resurfaced on a total depth of 9 m. Cofferdam were built 2 meter away from the piers to allow access to the sidewalls in “dry dock”. The resurfacing operations required the removal of a 25 cm thick layer of concrete from the sidewalls with power tools. Using an OceanSonics hydrophone, it was confirmed that the main sources of underwater noise in the harbour were jackhammers, gas-powered concrete saws and air hoses. It was required to maintain ambient sound levels below a median value of 102 dB re 1 µPa immediately outside the harbour. The project requirements additionally specified that if it were impossible to remain below this value at all times, sound-emitting activities were to be performed only during the October 1st to March 31st period. Other sound level parameters such as SELcum and SPLpeak were measured and monitored over the course of the project.
Because the stringent requirements for the protection of wildlife proved difficult to attain, a 30 m long BubbleTubing® was deployed in a crescent shape at approximately 5 m from the cofferdam to provide additional sound level control. The BubbleTubing® produces a dense “curtain” of rising bubbles that interacts with sound. Experimental results from this field project showed a global attenuation of the order of 10 dB. These results are analyzed in light of a controlled test phase conducted previously in 2018 in the Bedford Basin located in Halifax, Nova-Scotia. This case studies demonstrates that a bubble curtain can be an asset to protect marine mammals from underwater construction work.
OCCURRENCE OF IBUPROFEN AND 2-HYDROXY IBUPROFEN IN SAINT LAWRENCE RIVER
Pourya Zojaji, Hassan Alhachami, Esmaeel Kariminezhad, Shameem Jauffur, Zeinab Bakhshi, Marc-Antoine Vaudreuil, Sebastien Sauve, Maria Elektorowicz
Mr. Pourya Zojaji, Concordia University (Presenter) Mr. Hassan Alhachami Mr. Esmaeel Kariminezhad, Concordia University Dr. Shameem Jauffur, Envirogenique Mrs. Zeinab Bakhshi, Envirogenique Mr. Marc-Antoine Vaudreuil, University of Montreal Dr. Sebastien Sauve Dr. Maria Elektorowicz, Concordia University
The widespread occurrence of pharmaceuticals at the minute concentrations in surface waters has revealed emerging anthropogenic effects on the aquatic environment. In this work, to determine the exposure of the Saint Lawrence River to the Ibuprofen (analgesic and anti-inflammatory pharmaceutical product) and its respective 2-hydroxylated metabolite, a municipal wastewater treatment plant (WWTP) and its vicinity were monitored in three locations. Composite samples were taken on an hourly basis, filtered and homogenized in-situ. Automated solid-phase extraction coupled to liquid chromatography tandem mass spectrometry (on-line SPE LC-MS/MS) system was utilized to measure the concentration of selected compounds. The results revealed both compounds were present at the 100% frequency in the Saint Lawrence River. Ibuprofen (IBU) and 2-hydroxy ibuprofen (2-OH IBU) were measured at the concentrations ranging 3.64- 4.40 ng/l and 330-713 ng/l, respectively. Interestingly, the metabolite compound was present at significant higher magnitudes than the parent compound in all sampling sites alongside the river. Concentrations of 2-hydroxy ibuprofen were more remarkable in the downstream of the WWTP outfall where the metabolite level was measured 160-fold higher than the IBU. The results indicated special attention needs to be paid not only to the occurrence of the pharmaceutical active compounds but also their respective stable metabolites in the Saint Lawrence River. Such a conclusion is important considering this riverine ecosystem serves as a food and water source for the millions of people
Resuspension and settling of contaminated bottom sediments for application of removing contaminants from the lake bottom
Golnoosh Karimipourfard, Catherine Mulligan, S. Samuel Li
Ms. Golnoosh Karimipourfard (Presenter) Dr. Catherine Mulligan, Concordia University Dr. S. Samuel Li, Concordia University
This experimental investigation has been motivated by increasing scenarios of lakes receiving pollutants (heavy metals and nutrients) from various sources. Pollutants can enter the lake and accumulate over time in its sediments. Therefore, there is a need to effectively remove contaminants from the sediments. Field samples of non-uniform sediments from two contaminated lakes in Quebec were obtained and re-suspending of the sediments were examined for removing fine grain sized sediments. In general, the fine grains of contaminated sediment have larger amounts of pollutants adhered to their surfaces because of their higher specific surface area. Removal of these fine grains thus should effectively remove the pollutants. This research focuses on the re-suspension and settling behaviors of non-uniform sediments and the optimization of the removal of fine sediment grains. Laboratory experiments were conducted using a vertical cylinder of 20 cm in diameter and 50 cm in height. During the experiments, sediment samples from the lakes were deposited in tap water at a ratio of 1 gram of dry sediment to 10 ml of water. An air jet of about 10 m/s was injected at the bottom for 2 hours to ensure an even distribution of the sediment grains in the water. Immediately after this action, initial samples of well-mixed sediments and water were taken through an outlet hole in the cylinder wall, located at a height of 10 cm from the bottom. Initial grain sizes distributions were determined using a Laser scattering analyser. During sediment settling, subsequent samples were made every 5 minutes through outlet holes located at heights of 10, 15, 20 and 25 cm, respectively, from the bottom. The turbidity of the samples was measured using a turbidity meter. The sediment concentrations were obtained by measuring the amount of dried sediment on a filter and the volume of extracted water. The preliminary results show that fast settling of coarser gains occurred in the first few minutes. At a given height above the bottom, the grain size, turbidity and sediment concentration decrease with time. At a given time, they decreased with height. Thus in different applications such as phosphorus and heavy metal treatments, by identifying the range of sediments grain sizes which are carrying higher amounts of contaminant, we can target and remove them at the proper settling time and in the suitable height from the bottom which minimizes the amount of sediment removal in the resuspension technique.
Keywords: Sediment resuspension, sediment settling, sediment removal
Contracting and legal issues
A Comparative Analysis of Perceived and Revealed Levels of Competition in The Construction Industry and Its Implications for Technological Change
Sergiy Polyachenko, Jeff Rankin, Dhirendra Shukla, Yuri Yevdokimov
Mr. Sergiy Polyachenko, University of New Brunswick (Presenter) Dr. Jeff Rankin, University of New Brunswick Dr. Dhirendra Shukla, University of New Brunswick Dr. Yuri Yevdokimov, University of New Brunswick
This work-in-progress is dedicated to identifying the effect of market competition on innovations in the Canadian Construction Industry. Overwhelming competition and low profit margins that preclude construction firms from taking a risk and introduce innovations, are the two popular arguments used by scholars and industry practitioners to explain slow technological change in the construction industry. These claims are usually supported by verbal and analytical models, anecdotal evidence or case studies. However, there is a scarcity of data-supported research in this area. In addition, the existing data-based efforts do not provide a definitive answer as to whether market competition affects innovation in the construction industry and what the nature of such an effect is. In this work, we are using data derived from public tenders conducted in several Provinces of Canada and augmenting that data with surveys of Canadian construction firms. The ongoing survey is being conducted on the sample of companies identified as participants in public tenders between 2011-2018. The tendering data allows us to understand what companies bid on the projects, what projects attract more bids, what the range of bids is, and what bids and companies usually win tenders. The survey data provides insights on firmsâ€™ performance, managerial practices and innovativeness. Merging these datasets provides a unique perspective on market performance and innovativeness among Canadian construction companies. First, having survey and tendering data for the same set of companies allows for comparisons of self-reported and observed levels of market competition in the industry. Next, it allows for an analysis and comparison of correlation of revealed and perceived levels of competition with the likelihood of innovation, controlling for other economic characteristics of a firm. Finally, it allows for a test of the functional form of such correlation. For example, preliminary analysis of tendering data for the period of 2001-2010 confirms a high degree of seasonality in terms of the number of winning bids as well as their total value. In terms of competitiveness, the highest number of bids per project is usually submitted in the first and second quarters of the year and over 75% of contracts were awarded through tenders with two or less bidders, demonstrating a clear tendency to increase in market competition as project value decreases. Next, we update and merge tendering and survey data; compare perceived and revealed levels of competition and analyze how perceived and revealed levels of competition correlate with innovations.
CONTRACTUAL GUIDELINES FOR CONTRACTORS WORKING UNDER PROJECTS FUNDED BY SOUTHEASTERN US DOTS
Amr Elsayegh, Amr Elsayegh, Ibrahim Abotaleb, Christopher Smith, Mustafa Bootwala, Seifeldin Eteifa
Amr Elsayegh, Missouri University of Science and Technology Mr. Amr Elsayegh (Presenter) Dr. Ibrahim Abotaleb Mr. Christopher Smith Mr. Mustafa Bootwala Mr. Seifeldin Eteifa
Transportation projects in the infrastructure sector contribute to approximately 42% of the total expenditures on public construction projects in the US. The main source of funding of these projects is the taxpayer’s hard-earned money. The ever-growing problem by transportation projects is that the available funds are less than those required to have a stable and well maintained transportation network. Unnecessary costs in these projects are mainly caused by Conflicts, Claims and Disputes (C2D). According to recent reports, C2D in construction is greatly attributed to poor contract administration. The goal of this paper is to provide better understanding and utilization of contracts that are managed by the Departments of Transportations (DOTs) of 6 southeastern states: Tennessee, South Carolina, North Carolina, Georgia, Alabama and Florida. To this end, the authors: (1) analyzed the standard contract agreements published by these 6 states; (2) highlighted commonalities and differences in key subject areas including bidding, contract award, selection criteria, payment and control work. Usually, local contractors in southeastern areas work in their home states as well as in the neighbouring states. The outcomes of this work is that contractors conducting business in the southeast will benefit greatly from the presented contractual guidelines. This research method could be implemented in other states to cover different regions in the US. Ultimately, this will help in minimizing cost due to conflicts and disputes in projects; thus, making better use of the US taxpayer’s money.
Effective Tools for Projects Delivered by Progressive Design-Build Method
Simon Adamtey, Lameck Onsarigo
Dr. Simon Adamtey, Kent State University (Presenter) Dr. Lameck Onsarigo, Kent State University
Progressive design-build (PDB) is a new and distinctive method where an owner procures the services of a design-builder based primarily on qualifications or best value without final price and schedule commitment as part of the process. PDB leverages the benefits of design-build (DB) where one contractor is selected for both design and construction, and the benefits of construction manager-at-risk (CMAR) where the owner has input and control over the preconstruction phase. The collaboration between the owner and the DB team encourages innovation and provides performance guarantees. Being a new method coupled with a lack of long-term experience necessitates continued investigation of the effective tools and success factors for improved implementation. To this end, this research study was conducted to further facilitate research and applications of PDB. This paper discusses the results of a comprehensive literature review and analysis of current applications. Publications including journal articles, conference proceedings, case studies and reports were reviewed. The analysis revealed that some of the effective tools include owner education, risk assessment criteria, project selection criteria, proposal evaluation criteria, balanced collaborative contract, project packaging, open book pricing and continuous evaluation. Additionally, the paper addresses the differences between PDB and DB, the benefits of PDB, and the challenges and potential obstacles to a successful PDB delivery. This paper contributes to the existing PDB knowledge facilitating further research and applications by both academic and industry stakeholders.
How and why use a Code of Standard Practice for Structural Steel
Donâ€™t we all want to prevent and resolve project disputes? Of course, we do! More importantly however, we first need to be informed and understand the effective tools that available to us and secondly, we must ensure that we integrate their usage in our projects. The purpose of this paper is not to give a detailed rendition of the articles of the CISC Code of Standard Practice, but rather to present a partial and cursory summary of some of the responsibilities and obligations of the key stakeholders, as outlined in the Code and typical in Codes od Standard Practice. A real case example will be presented and will serve as a good illustration of the critical importance in the Code, its application and effective use to prevent and/or resolve projet disputes. The objective of the author of this paper is to provide a cursory overview of some key aspects of the Code. It should be noted that direct content of the Code is repeatedly used in this paper, to reiterate the substantive significance of the articles on the global perspective of this paper. The Code has a plethora of information that is critical for projects, but this paper will cover a few items as food for thought for all stakeholders, such that they appreciate the importance of specifying this type of document in the contract documents.
Investigation of Conflictâ€™ Impacts On Engineering, Procurement, and Construction Schedule Performance
Sharareh Kermanshachi, Elnaz Safapour, Thahomina Jahan Nipa, Shirin Kamalirad
Dr. Sharareh Kermanshachi, University of Texas at Arlington (Presenter) Mrs. Elnaz Safapour, University of Texas at Arlington Ms. Thahomina Jahan Nipa, University of Texas at Arlington Ms. Shirin Kamalirad, University of Texas at Arlington
Most construction projects are subject to disagreements between the primary stakeholders (owners, engineers/designers, and contractors) which, if not addressed and resolved in a timely manner, become very time-consuming and costly. Although these conflicts and disagreements have the potential to adversely affect project schedule performance and success, their undesired consequences have been rarely studied. Therefore, the aim of this study is to investigate the impact of internal and external conflicts of the primary stakeholders on Engineering, Procurement, and Construction (EPC) schedule performance. To achieve these objectives, potential conflict scenarios were initially defined. Then, 30 completed case study projects were collected and analyzed. The results reveal that the conflicts within the contractor entity have seriously affect design and procurement schedule performance. This study provides guidance to project decision-makers, helping them plan proactively how to avoid and/or mitigate conflicts at the early stages of construction projects’ lifecycle.
Simulation-based Framework for Construction Delay Analysis
Muaz Fagiar, Yasser Mohamed, Simaan AbouRizk
Mr. Muaz Fagiar, University of Alberta Dr. Yasser Mohamed, University of Alberta (Presenter) Dr. Simaan AbouRizk, University of Alberta
The most common types of construction disputes relate to schedule impacts, or delay claims. They are caused by unanticipated events that extend the project and/or prevent its execution from being performed as originally planned. Yet, they are the least understood and most complex disputes in the construction field. Various schedule delay analysis methods have been developed and used. Among them, window-based delay analysis methods have been recognized as the most credible methods, however, they still have functional limitations and use prerequisites. This study discusses some of the outstanding drawbacks, identifies new issues and demonstrates inaccuracies in some of the proposed methods. To improve delay analysis practices, a new framework for forensic delay analysis is introduced. The framework takes full advantage of a time-step simulation approach to model project data, analyze delay claims, and quantify both acceleration and time extension award. Details of the simulation-based framework are introduced along with demonstration of its merit over existing delay analysis methods. The proposed framework is applicable for both prospective and retrospective delay analysis situations.
Corrosion/ Potential of structures
Optimizing the Performance of Galvanized Reinforcement for Corrosion Protection
Shannon Pole, Martin GagnÃ©, Frank Goodwin, Gary Dallin
Ms. Shannon Pole, International Zinc Association (Presenter) Mr. Martin Gagné, International Zinc Association Dr. Frank Goodwin Mr. Gary Dallin, Galvinfo Centre
Corrosion of steel reinforcing bar (rebar) is the most significant cause of concrete failure, resulting in expensive repairs and premature replacements across the country. This presentation will discuss proven low-cost zinc coating processes for reinforcing steel. The properties of this new coated rebar and its contribution to improvement of concrete performance will be presented together with the status of related national and international standards.
Hot-Dip Batch Galvanizing of steel is a proven technology that has been in use for over 100 years, protecting structures exposed to marine and deicing salt environments from deterioration. This technology has been applied to reinforcing steel for over 50 years, with most structures still operating and in good condition today.
The Continuous Galvanized Rebar (CGR) coating process is similar to galvanizing of sheet steel. As an in-line process, the bar is fluxed, induction heated and coated with a uniform zinc layer in a matter of seconds. With reduced production time, CGR requires shorter lead times than current corrosion resistant bars. The zinc coating applied is durable and resistant to abrasion that is routine during transport and construction.
Additionally, the coating is also highly ductile and can be bent without cracking to diameters of less than 4x the rebar diameter. This property ensures the bars can be pre-fabrication, reducing cost and accelerating construction schedules.
Once in the concrete, the zinc coating protects the rebar both as a barrier coating and with the well-known sacrificial properties of a galvanized coating. Test results indicate that the use of galvanized rebar with high quality concrete and customary depths of concrete cover will enable rebar to be protected for 100 years.
The ability to greatly extend the life of concrete bridges by using galvanized rebar is important to maximize the public investment in infrastructure projects. Life cycle cost analysis confirms that using a zinc coated bar from the beginning of a project reduces the future maintenance needs of the bridge and significantly reduces cost over the life of the project. Many bridge maintenance plans require zinc anodes to be used to extend bridge life. Bridges that use zinc from the beginning already benefit from the sacrificial properties of the metal, delaying the need for maintenance programs to prolong bridge life.
From coating to placement to maintenance, CGR contributes positively to accelerated bridge construction and offers extended corrosion protection, extending bridge life and reducing life cycle costs.
Potential Incorporation of Saline Water into Portland Cement Concrete
Dalia Ibrahim, Mariam Abdel Wahed, Mahmoud Abo Khazana, Mostafa Farouk, Mohamed Aly, Athnasious Ghaly, Reem Abou Ali, Magdi Madi, Mayer Farag, Moustafa El Assaly, Mohamed N. Abou-Zeid
Ms. Dalia Ibrahim, The American University in Cairo Ms. Mariam Abdel Wahed, American University in Cairo Mr. Mahmoud Abo Khazana Mr. Mostafa Farouk, AUC Mr. Mohamed Aly, AUC Mr. Athnasious Ghaly, American University in Cairo Ms. Reem Abou Ali Mr. Magdi Madi, The American University in Cairo Mr. Mayer Farag, The American University in Cairo Mr. Moustafa El Assaly, Mr Dr. Mohamed N. Abou-Zeid, The American University in Cairo (Presenter)
Fresh water scarcity is one of the major concerns in the world nowadays due to amid global warming and rapid increase of population. The population is escalating significantly and is expected to reach its critical peak by 2050 leaving 2.8 billion people in 48 countries facing water scarcity. Against this background, this study investigates the potential incorporation and feasibility of replacing fresh water with seawater as mixing water as well as curing water in concrete manufacturing. To meet this objective, various mixtures were prepared with various levels of strengths while incorporating different corrosion protection measures to minimize steel corrosion. The properties of the concrete are evaluated through fresh tests as slump, unit weight, air content and temperature, mechanical properties namely compressive strength and flexural strength and accelerated corrosion testing through impressed voltage method. A feasibility study is conducted to quantify the cost savings resulting from replacing freshwater with seawater in mixing and curing concrete. This work is expected to achieve better understanding of concrete behavior when seawater is incorporated. The study will attempt to identify measures for careful incorporation of sea water into concrete. A case study for an actual mega project in a coastal area is presented to highlight the pros and cons for such incorporation and the potential feasibility attained.
Decision-support systems (1)
A decision support tool for management of small residential renting buildings: A case study
Adel Francis, Virginie Mathieu
Dr. Adel Francis, ETS Mrs. Virginie Mathieu, ÉTS (Presenter)
It is commonly known that the Montreal metropolitan area’s real estate is getting older. The existing management tools for real estate assets consider, for the most part, only large buildings. In the past, it became clear to the actors in the real estate industry that managing tools for large buildings becomes quickly profitable for the owners. However, in the Montreal metropolitan area, those types of residential buildings represent a minority of the real estate. When looking at smaller residential renting buildings, few tools are available and applicable. Therefore, the owners or managers of this type of residential building rely on their judgment to decide whether they will make improvements to their buildings. Their budgets are also based on this decision. This type of management increases the risk of unexpected events caused by bad maintenance of the components. Planned interventions would reduce the risk of those events occurring. In this paper, a decision support tool is presented to plan interventions in the management of small residential renting buildings. In fact, the decision support tool shows an overview of the actual state of the buildings and helps the manager to optimize the operating costs and the overall health over the buildings’ life cycle and to plan the annual budget and work to be done. A case study will show the benefits of using this tool for residential renting buildings.
A Fund-Allocation Optimization Framework for Prioritizing Historic Structures’ Conservation Projects - An Application to Historic Cairo
Dina Saad, Ahmed Elyamani, Maha Hassan, Sherif Mourad
Ms. Dina Saad, Cairo University (Presenter) Dr. Ahmed Elyamani, Cairo University Dr. Maha Hassan, Cairo University Dr. Sherif Mourad, Cairo University
Egypt is famous for its cultural heritage and historic attractions that span thousands of years. This cultural heritage is one of the tourism industry motors which contributes significantly to the country’s gross domestic product (GDP). Historic Cairo has been declared as a UNESCO World Heritage Site for having hundreds of mesmerizing historic Islamic and Coptic structures; however, tourism-revenues are quite small relative to the ones generated from the famous red sea resorts and Luxor and Aswan ancient sites. This is because most of these structures are partially or completely closed due to the need for restoration and/or their poor structural condition. However, conserving these structures is quite challenging due to its complexity, lack of funds for restoring hundreds of historic structures, and lack of structured funding system. Therefore, this paper proposes a framework for a new multi-objective optimization model that prioritizes competing historic structures for the limited funding available while maximizing the structural physical performance and the socioeconomic benefits over a specified planning horizon, considering: the expected deterioration behavior over the funding period, vulnerabilities to further damage, costs associated with the conservation method, and the structure’s relative importance in terms of its value. In essence, the new model will help decision makers determine the optimum restoration plan to open the deteriorated historic structures to the public, and thus increase tourism-based revenue generating streams to rejuvenate the tourism sector in Historic Cairo, and have a positive impact on Egypt’s economy.
A System Dynamics model of client linked delay in construction of building projects in India
Clients are among the major stakeholders in construction projects and therefore play crucial roles in the completion of the projects. However, it is also argued that client induced factors contribute to cause delay in construction projects in India. Therefore, the objectives of the investigation are to identify the influential client related variables, which cause delay; to evolve the causal feedback relations among the most influential client linked variables and delay; and to develop a System Dynamics (SD) model to examine the scenarios of delay under varied strategic conditions. For this purpose, a questionnaire survey was conducted among 120 willing stakeholders and professionals that include clients, contractors, project managers, consultants, designers, engineers, supervisors, suppliers, skilled construction labours etc., from various building projects in the Odisha state in India using random sampling process. Followed by a SD model was developed by using data from medium sized building projects from Odisha State in India to simulate and examine the behaviour of the project schedule and delay under different simulated scenarios, and estimate the reduction of delay under different policy interventions based on the dynamic hypotheses framed. Findings suggest that delay in progress of payments by owner, slowness in decision making process by owner, change orders by owner during construction, poor communication and coordination by owner and other parties, late in revising and approving the design documents by owner, delay in approving shop drawings and sample materials by the owner, and delay to furnish and deliver the site to the contractor by the owner are the major client/owner related factors, which cause delay. However, the modelling effort revealed that timely decision making which can be augmented by the availability of requisite information, and effective communication conjoined with the availability of fund and adequate budget allocation can ensure timely progress in payment that essentially shall able to reduce construction delay significantly. The contributions of the investigation are (1) it could assist the project stakeholders particularly the clients, contractors and project managers to diagnose the client linked challenges through the mechanisms that are created by the causal feedback relations; and (2) it also could enable the stakeholders to foresee the impacts of different causal feedback relationships and policy interventions on the reduction of delay quantitatively based on which appropriate actions to resolve the challenges of delay in construction projects in India can be taken.
Keywords:Client; Communication; Construction; Fund; System Dynamics modelling
Bid/No Bid decision using fuzzy risk assessment
Emad Elbeltagi, Ahmed Elhakeem, Sameh Abu Elsoud, Mohamed Megreya
Emad Elbeltagi Dr. Ahmed Elhakeem, AASTMT (Presenter) Dr. Sameh Abu Elsoud Mr. Mohamed Megreya
Bid / No-Bid decisions for large number of projects for construction companies can be cumbersome, tedious and complex task due to the uncertainty, uniqueness of each project and numerous internal and external factors. Contractors’ reputation is generated through the successful completion of projects contractors execute each year. The goal of construction companies is to keep their projects profitable while being executed in line with contractors’ ambition to be an industry leader in sustainability. The profitability of contractors depends on the success of their projects which can be achieved only with an appropriate bid/no bid decision system.
This paper introduces a comprehensive two-stage bidding assessment framework for the contractors. The proposed approach helps evaluating the bid/no bid decision and removing any ambiguity that may be associated with the decision process. A competency group scored heat map model to exclude projects with an unattractive opportunity/risk profile as much as possible and as early as possible during the selection phase and a project risk model using fuzzy logic to decide whether to bid or not to bid. The proposed framework is expected to help contractors improving the bidding strategy and ensuring that an efficient bidding processes is in place, as well as relevant resources.
EVALUATING THE ECONOMIC EFFECTIVENESS OF DECONSTRUCTION ACTIVITIES FOR A FACILITY: A CASE STUDY
Akash Pushkar, Yujie Wei, Burcu Akinci
Mr. Akash Pushkar, Carnegie Mellon Univeristy (Presenter) Mr. Yujie Wei, Carnegie Mellon University Dr. Burcu Akinci, Carnegie Mellon University
Construction and demolition of buildings produce 136 million tons of debris per year in the US, with demolition alone accounting for 48% of the total construction waste stream. In the past, several researchers have reiterated the significance of ’deconstruction’, a systematic disassembling of a structure, instead of demolition for reducing waste and increasing reuse. They have listed numerous environmental benefits and a cost saving of approximately £1.3 billion on haulage and landfill tax. Since deconstruction is a complex and costly process, it is important to assess the candidacy of a building for deconstruction as ‘suitable’/‘unsuitable’ beforehand. Candidacy is assessed by considering environmental and economic factors. For this purpose, the economic viability of the entire process, consisting of expenditures, such as the cost of labor and cost of disposal, and earnings, such as resale/salvage value of the material, need to be examined before deconstruction commences. Prior research studies have compared the value of deconstruction to demolition in case studies of buildings that were not designed for deconstruction. As facilities get designed with deconstruction in mind, the impact of deconstruction activities is expected to increase.. The research described in this paper assesses the economic benefit of deconstruction as compared to demolition activities in a case study of a building designed for deconstruction. In this case study, we evaluated the economic viability of a deconstruction project based on the quantity of material recovered and different cost incurred, such as labor, material, equipment and administration costs, and explored whether the deconstruction was beneficial over demolition for the case study building. Cost-benefit analysis (i.e. total benefits - total cost) was used for evaluating the economic viability of deconstruction and it showed that deconstruction was significantly beneficial, with savings of 105%, than a demolition case scenario for the same building. This amount of saving can be attributed to the fact the facility was originally designed for deconstruction.
Introducing the concept of Foundational Attributes of construction projects
Fan Zhang, John Gambatese
Dr. Fan Zhang, University of Southern Mississippi (Presenter) Dr. John Gambatese, Oregon State University
A construction project is considered to be unique due to the process of delivering a customer-designed product, diverse stakeholders involved, the unique location and timeframe of construction, and specific social, economic, and environmental constraints attached to it. The uniqueness of construction projects brought great challenges to the construction industry professionals as well as researchers and educators in the construction discipline. If a method or a model can be developed to assess the similarity between projects and make project comparison more science than art, we can increase the confidence level of researchers when they conduct analyses and make conclusions. We can help industry professionals make better decisions based by providing more accurate information. This paper introduces the concept of Foundational Attributes of construction projects. A literature review is conducted to create the framework, and case study projects are applied to the framework to demonstrate how this concept helps with project comparison. A spider chart is chosen to host the concept of Foundational Attributes, and two case study projects are selected to demonstrate how to quantify project similarity using the concept of Foundational Attributes and a spider chart. Last but not least, lessons learned and future research directions are discussed at the end of this paper.
THE USE OF RELIABILITY ANALYSIS IN THE BID DECISION-MAKING PROCESS
Farzad Ghodoosi , M. Reza Hosseini, Ashutosh Bagchi
Dr. Farzad Ghodoosi , Concordia University (Presenter) Dr. M. Reza Hosseini, Deakin University Dr. Ashutosh Bagchi, Concordia University, Canada
Generally, bid offers are prepared based on the contractors’ intuition and experience. In this process, quantification of risk elements influence bid pricing and their corresponding impact is being done within a non-systematic approach. Client’s reputation or the record of the projects owned by the client has a vital contribution on the issue. In this study, using reliability analysis, a practical quantitative framework is developed which enables contractors make informed bid/no-bid decisions based on estimating the probabilities of the schedule and cost overruns. Thereafter, the expected value of those risk elements are estimated to calculate a reasonable bid price. The developed risk model is here adopted in estimating the bid price for the construction of a low-rise university building based on the empirical data obtained from 40 similar projects already owned by the client. The contribution of this study is to develop a cost-effective, simple and rapid method applicable in bid decision-making processes.
Would Québec Reach the Electric Vehicle Adoption Target? - A Game Theory Approach
Rafaela Panizza, Mazdak Nik-Bakht
Ms. Rafaela Panizza, Concordia University (Presenter) Dr. Mazdak Nik-Bakht, Concordia University
As the awareness to decrease greenhouse gas (GHG) emissions rises, so do the Québec action plans to improve its own rate of emission. One of the main plans is the “Transportation Electrification Action Plan”, which directs the government into new targets for electric vehicle (EV) adoption with a combination of programs. With 4 years of plan, the trend does not look promising to achieve the first set target (100,000 EVs by 2020). This study is modeling the Québec market as a game of strategy, played two main players (government and consumer) each aiming to maximize their own utility. This game is being analyzed for evaluation of feasibility of action plan targets, and the costs associated with it. The game is a perfect information extensive game that analyzes the EV consumers’ response to a change in financial incentive programs. The moves and payoffs of the game were based on available data. Results of this study showed that the government has multiple alternatives to reach the final 2026 target however, the time for making changes is crucial when analysing the economic benefits that the government can acquire. Finally, due to the limited reported experiments that Québec consumers have with the EV market; the simulation of EV adoption has its limitations. This is an initial effort to simulate the EV market in Québec, following steps of this work include the analysis of different segments of prospective users, so that in the future more accurately effective incentives can be known.
Keywords: electric vehicle, financial incentive, consumer centered model, smart city, strategic planning, policy making.
Decision-support systems (2)
AHP based approach for crane selection of building construction in Saudi Arabia: A case study
Adel Alshibani, Hashim El-Assir, Mustafa Alnajjar, Hamza Hamida
Dr. Adel Alshibani, KFUPM (Presenter) Mr. Hashim El-Assir Mr. Mustafa Alnajjar Mr. Hamza Hamida, King Fahd University of Petroleum and Minerals (KFUPM)
Cranes are essential equipment used in the construction industry to hoist and place loads. The selection of the proper type of crane is challenging task to project management team. The challenge arises due to the involvement of many factors in the selection process. This paper presents a case study of the selection of the suitable crane in the construction of precast apartment buildings compound in Jubail City in KSA. The approach applied in the selection process is based on Analytic Hierarchy Process (AHP) technique which is capable of solving multi-criteria decision making (MCDM) problem. AHP is utilized to assess the significant influence of the identified main and sub criteria on the selection process. Both quantitative and qualitative criteria are considered in this study through a pairwise comparison. The identified crane alternatives in this study are tower crane, crawler mobile crane, and wheeled mobile cranes. Based on reviewing previous studies and meetings with local experts, 8 criteria of selection were identified which are load lifting frequency and capacity, structure height, project duration, purchase/renting cost, delivery, installation and disassembly, productivity, ground condition, and safety. The safety criteria has a sub-criterion including operator proficiency, wind, and visibility. The results obtained from the AHP showed that the best crane alternative of is the wheel mobile crane.
Keywords: AHP, Crane, selection, KSA, precast
ANALYSIS OF PREFABRICATED CONSTRUCTION: PRODUCTIVITY, BENEFITS, RISKS & APPLICATIONS IN CANADIAN PERSPECTIVES
This study analyzes the productivity of prefabricated construction methods with respect to cost and time. In addition, this study explores the main benefits and applications of prefabricated construction methods as well as identifies the major risks that could affect their use in Canada. Several interviews with experienced construction professionals were conducted. Also, surveys were conducted choosing construction managers, tradespeople, and construction workers who are familiar with prefabricated construction. The responses from construction professionals revealed that prefabricated construction methods are more advantageous than conventional construction methods due to reduced construction time, cost, and site waste. The interview results indicated that prefabrication construction methods take about 3 to 4 weeks per townhouse unit and can save around 4 to 8 weeks. Furthermore, the survey results exhibited that prefabricated construction methods decrease the overall project delivery time. The survey results also imparted that faster project delivery time and reduced labourers on site are the two most important factors, which decrease the cost of prefabricated construction. The other benefits of prefabricated construction methods are minimum risk of injury and minimization or total elimination of on-site wet trades, which became obvious from the interview results. Despite having manifold benefits, there are some risks of using prefabricated construction methods, such as fabrication errors, damage during transportation, misfits on worksite, and delays due to the shortage of skilled labourers and changed orders. Yet prefabricated construction methods are being used in Canada in the cases of trusses, exterior wall components, framing elements, and MEP (mechanical, electrical, plumbing) systems.
MULTI-PERIOD LOCATION OPTIMIZATION OF NEW PUBLIC FACILITIES TO MAXIMIZE EQUITY IN ACCESS AND CAPACITY-SATURATION
In this paper, the multi-period facility location problem is introduced where the goal is to determine the location of new facilities over a finite time horizon so as to maximize equity, while satisfying all the demand in each time period. In the introduced model, the selection of the location of the new facilities is limited to a number of potential sites. In addition, the number of new facilities that can be opened in each time period is bounded by a budget constraint. The proposed formulation aims to optimize coverage while balancing the excess flow at capacity-saturated facilities. We propose to minimize the sum of demand-weighted travel distance to schools and the total excess flow at supplying facilities. A deterministic analysis was performed to estimate the values of all the uncertainties, including the demand in each time period. An illustrative case study on Sydneyâ€™s public school network is presented where the location of new schools is determined during a planning horizon extending over 4 years and split into 4 time periods. The proposed model provides decision makers with the needed tool to improve the provision and maximize equity in locating new public facilities over a multi-period planning horizon
Saving refinancing cost: the option value of Revenue Risk-Sharing Mechanisms in transportation public-private partnerships (P3) projects
Yunping Liang, Baabak Ashuri
Mr. Yunping Liang (Presenter) Dr. Baabak Ashuri, Georgia Tech
Uncertainties about total construction cost and operational revenues are two major risk factors in transportation P3 projects. These uncertainties put projects at risk of being unable to fulfill annual debt repayment obligations. When a project generates insufficient cash flow to service the debt in a certain year, it normally has to go for short-term financing by borrowing short-term loans. With the help of revenue risk-sharing mechanisms (RRSMs), supported projects may be able to get rid of unexpected interest disbursement. The objective of this paper is to critically examine and compare the option value of Contingent Finance Support (CFS) and Minimum Revenue Guarantee (MRG) in terms of saving refinancing cost for debt repayment. An integrated real options valuation model is created that utilizes a decision analysis method for pricing the technical project risk and a risk-neutral option pricing method for pricing the market risk. The integrated model quantifies the construction risk using the subjective probability distribution. The model prices the option value of RRSMs on saving project refinancing cost with consideration of market risk premium for uncertain traffic volume. The proposed model helps stakeholders better understand and measure the burden of assuring annual debt repayment under uncertain cash flow. The private sector can use the proposed model to evaluate the value of the RRSMs provided by the government in terms of reducing refinancing cost.
Decision-support systems (3)
A Machine Learning-Based Approach for Building Code Requirement Hierarchy Extraction
Ruichuan Zhang, Nora El-Gohary
Mr. Ruichuan Zhang, University of Illinois at Urbana-Champaign (Presenter) Ms. Nora El-Gohary, University of Illinois at Urbana-Champaign
To reduce the time, cost, and errors of compliance checking, various automated code compliance checking (ACC) methods have been developed and implemented. Although these methods have achieved different levels of automation, representativeness, and accuracy, most of them are unable to fully automatically convert complex building code requirements into computer processable forms. Such complex requirements usually have hierarchically complex clause and sentence structures (e.g., nested syntactic and semantic structures, conjunctive and alternative obligations, multiple exceptions, etc.). There is, thus, a need to decompose such complex requirements into hierarchies of much smaller, manageable requirement units that would be processable using most of the existing ACC methods. Rule-based methods have been used to deal with such complex requirements and have achieved high performance. However, they lack scalability, because the rules are developed manually and need to be updated and/or adapted when applied to a different type of building code. More research is, thus, needed to develop a scalable approach to automatically convert the complex requirements into hierarchies of requirement units to facilitate the succeeding steps of ACC such as deep information extraction, information transformation, data matching, and compliance reasoning. To address this need, this paper proposes a new, machine learning-based approach to automatically extract the aforementioned requirement hierarchies. The proposed approach consists of three primary tasks: (1) model the requirement hierarchies, requirement units, and relationships between the units; (2) use a machine learning-based approach to automatically segment the building code requirement sentences into requirement units; and (3) use natural language processing techniques to automatically detect the relationships between requirement units, both within a sentence and between sentences of multi-sentence requirements. The proposed approach was implemented and tested on a number of chapters from the 2009 International Building Code (IBC) and the Champaign 2015 IBC Amendments, and was evaluated using precision and recall. The preliminary results show that the proposed approach is able to extract the requirement hierarchies from different types of complex requirements, with high precision and recall. The paper also discusses how the requirement hierarchies can be used in the succeeding steps of ACC such as deep information extraction.
Application of Fuzzy Analytic Hierarchy Process in Front-End Planning
NEBIYU Kedir, Maedeh Taghaddos, Mohammad Raoufi, Aminah Robinson Fayek
Mr. NEBIYU Kedir (Presenter) Mrs. Maedeh Taghaddos, University of Alberta Dr. Mohammad Raoufi, University of Alberta Dr. Aminah Robinson Fayek, University of Alberta
Project success is dependent upon the proper implementation of front-end planning (FEP) throughout those phases of a construction project’s life cycle that precede the design stage. FEP requires that project stakeholders produce a systematic scope definition and alignment. This process necessarily involves uncertainties since stakeholders occupy different roles and have different objectives. Furthermore, the limited availability of project-specific knowledge during the process of scope definition and alignment usually adds to the uncertainty associated with FEP, therefore requiring that project participants work within ‘acceptable tolerances’ to arrive at a consensus on project objectives and planning. Findings from the Construction Industry Institute (CII) indicate the frequent presence of misalignments between engineering and construction work packages that hinder the execution of installation work packages. These misalignments also introduce uncertainties to the implementation of FEP that need to be addressed.
Currently, CII uses two methods—the Project Development Rating Index (PDRI) and the Alignment Thermometer—to measure the level of scope definition and alignment in construction projects. However, these CII methods cannot adequately address the aforementioned uncertainties. For example, current CII methods lack approaches that can handle subjective variables and linguistic imprecision when addressing both alignment and scope definition issues. There is a need to explore new approaches that incorporate tools that can handle imprecise language more efficiently.
In this study, the fuzzy analytic hierarchy process (FAHP) is used to weigh and aggregate different stakeholders’ definition levels of project components and arrive at a PDRI score that recognizes the uncertainties that exist in construction. In addition, a methodology is developed for producing an Alignment Thermometer that captures the subjective uncertainties associated with stakeholders’ interests and levels of expertise. The results of this study demonstrate that approaches incorporating the FAHP can more effectively handle uncertainty in the FEP process than current CII approaches.
Artificial Neural Network Deterioration Assessment Model for Bridges in Missouri
Gasser Ali, Amr Elsayegh, Rayan Assaad, Amr Elsayegh, Ibrahim Abotaleb
Mr. Gasser Ali (Presenter) Mr. Amr Elsayegh Mr. Rayan Assaad Amr Elsayegh, Missouri University of Science and Technology Dr. Ibrahim Abotaleb
Missouri has the seventh largest number of bridges nationwide, yet must maintain its inventory with funding from just the fourth lowest gasoline tax in the country. Estimation and prediction of the condition of bridges is necessary to create and optimize future maintenance, repair, and rehabilitation plans as well as to assign the necessary associated budgets. Previous studies have used statistical analysis, fuzzy logic, and Markovian models to develop algorithms for predicting future bridge conditions. Due to the non-linear nature of the relationship between the characteristics of bridges and their deterioration behavior, Artificial Neural Networks (ANN) have shown to be more suitable for discovering and modeling such relationship. As such, there is a gap in the literature when it comes to the ability of bride condition estimating. The goal of this research is to develop an ANN deterioration assessment model in Missouri. To this end, data on long span bridges was used where 80% of the data points were used for training and 20% were used for testing. In addition, a linear regression model was developed to act as a benchmark to assess the performed of the proposed ANN. The developed framework was successfully able to predict future condition of bridges. By using the developed model, the Missouri Department of Transportation will have a better ability to optimize their funding allocation and timing of bridge maintenance, repair, and rehabilitation. While this model was applied to bridges in Missouri, it can be tailored for other bridge assessment operations nationwide.
Assessment of Project Risks in Fast-Track Construction Projects: An Evaluation of Risk Mitigation Responses
Claudia Garrido Martins, Susan M. Bogus, Vanessa Valentin
Ms. Claudia Garrido Martins, The University of New Mexico (Presenter) Dr. Susan M. Bogus, University of New Mexico Dr. Vanessa Valentin, University of New Mexico
Risk mitigation is an integral part of a risk management process. The planning and evaluation of the risk responses or strategies close the loop on the risk management cycle. The goal of this study is to develop a risk mitigation approach applied to fast-track projects. Risk mitigation is the last phase of the risk assessment framework for fast-track construction projects developed by the authors. Although the study of risk mitigation is not new in the area of construction, the authors did not find evidence that the study of risk mitigation when construction project activities are overlapped was explored. Therefore, the specific objectives of this study are (1) quantify the ability of the risk responses/strategies to mitigate the risks and the overall impact on the project target performance metrics, and (2) determine the impact boundaries of the risks and the optimal combination of the risk responses or strategies that would minimize the project’s risk exposure and minimize the mitigation costs. A conceptual model was developed to assess the mitigation responses/strategies using a Monte Carlo simulation model and an optimization Pareto Front analysis to find the optimal combination of the risk responses. The model considered the application of risk responses and new values for the probability of occurrence and impact respectively for each level of overlapping, the mitigation costs, and a contract bonus. The output of the model includes: the new probability of attaining the desired fast-track project duration under different risk scenarios considering the mitigation actions, the most probable duration of the project, and the trade-off between the total risk mitigation cost and the possible project bonus for early completion, with the optimum overlapping combination that can produces the most satisfactory trade-off. The implication of the results should be interpreted according to the organization, the decision-maker risk tolerance, and the available resources. However, the result can show that the planned risk responses applied might not be sufficient to promote a significant change in the project’s risk exposure. Moreover, the optimization results might show that it is possible to obtain an overlapping combination that can produce a satisfactory bonus-risk mitigation cost trade-off, meaning that it might be worthy to expend financial resources and try to mitigate the risks that can compromise the fast-track strategy of the project, considering that the mitigation cost is less than the bonus that can be awarded.
City-Scale Energy Modeling to Assess Impacts of Extreme Heat on Electricity Consumption and Production using WRF-UCM modeling with Bias Correction
Elham Jahani, Soham Vanage, David Jahn, Kristen Cetin, William Gallus, Phong Nguyen, Youngchan Jang, Eunshin Byon, Lance Manuel
Ms. Elham Jahani, Iowa State University Mr. Soham Vanage, Iowa State University Mr. David Jahn, Iowa State University Dr. Kristen Cetin, Iowa State University (Presenter) Dr. William Gallus, Iowa State University Mr. Phong Nguyen Mr. Youngchan Jang, University of Michigan Dr. Eunshin Byon Dr. Lance Manuel, University of Texas at Austin
The energy consumption of buildings at the city scale is highly influenced by the weather conditions where the buildings are located. Thus, having appropriate weather data is important for improving the accuracy of prediction of city-level energy consumption and demand. Typically, local weather station data from the nearest airport or military base is used as input into building energy models. However, the weather data at these locations often differs from the local weather conditions experienced by an urban building, particularly considering most ground-based weather stations are located far from many urban areas. The use of the Weather Research and Forecasting Model (WRF) coupled with an Urban Canopy Model (UCM) provides means to predict more localized variations in weather conditions. However, despite advances made in climate modeling, systematic differences in ground-based observations and model results are observed in these simulations. In this study, a comparison between WRF-UCM model results and data from 40 ground-based weather station in Austin, TX is conducted to assess existing systematic differences. Model validation was conducted through an iterative process in which input parameters were adjusted to obtain to best possible with the measured data. To account for the remaining systemic error, a statistical approach with spatial and temporal bias correction is implemented. This method improves the quality of the WRF-UCM model results by identifying the statistic properties of the systematic error and applying the bias correction techniques.
Construction Stakeholdersâ€™ Perception toward the Success Factors of Construction Projects
Ahmed Al-bayati, Mostafa Namian, Kasim Alomari
Dr. Ahmed Al-bayati, Western Carolina University (Presenter) Dr. Mostafa Namian, Western Carolina University Dr. Kasim Alomari
Each construction project has unique characteristics that require creative yet different management techniques to tackle and address the associated challenges. However, despite the dissimilarities in their nature, all construction projects are intended to be successful and profitable. A successful construction project is generally defined that the project that has been completed within the intended time frame and budget, with acceptable quality, and no serious work-related injuries. In other words, a proper and effective management style aims to achieve the project goals concerning safety, quality, cost, and time. Due to the dynamic nature of construction projects, managers often need to trade-off these underlying factors of success to address the existing project constraints. Construction managers often prioritize one factor over the other to lead, convince, and motivate the intermediate-level managers (i.e., superintendents) and workers to follow their plan to complete the construction projects successfully. In fact, similar perception is the glue that holds all stakeholders to collaborate and work towards the same goals. On the other hand, although the existence of different perceptions is normal and inevitable, the difference in perceptions toward the main objectives raises challenges and causes issues that may hinder the success of construction projects. Therefore, the purpose of this study is to 1) assess how construction managers perceive the relative values of safety, quality, cost, and time and 2) examine the difference between the perceptions of project managers and intermediate-level managers (i.e., superintendents) and construction workers. To fulfil the research objectives, 48 construction managers across the U.S. were contacted to participate in a survey designed to quantify the perceptions concerning safety, quality, cost, and time. The results showed that safety has the highest relative importance in the perception of managers compared to the other factors (i.e., quality, cost, time). Also, the findings revealed that there is a statistically significant difference between the perception of project managers and superintendents concerning project cost but not the safety, quality, and time. The current findings comply with the existing body of literature emphasizing the importance of safety. This research can help construction professionals and practitioners to identify the difference in the perceptions among key players and enhance the managerial efforts to align dissimilar views towards the success of construction projects.
A Systematic Approach to Analysis and Prioritization of Socioeconomic Policies and Legal Barriers to Rapid Post-Disaster Reconstruction
Behzad Rouhanizadeh, Sharareh Kermanshachi
Mr. Behzad Rouhanizadeh, University of Texas at Arlington Dr. Sharareh Kermanshachi, University of Texas at Arlington (Presenter)
The barriers leading to delays in the post-disaster recovery phase is an important concern for decision-makers. Among different barriers of timely post-disaster recovery, policy and legal barriers are of high importance according to their fundamental role. The aim of this paper was to identify and categorize the policies and legal barriers which affect post-disaster recovery processes in the U.S. For this purpose, over 200 scholarly papers were comprehensively reviewed. Through the review, fifty-eight potential policy and legal barriers to post-disaster recovery timeliness were identified, categorized, and finally, weighted and ranked. The seven categories included coordination, resources and documentation, construction and infrastructure, location, finance and economic, social and community participation, and approach and attitude. Subject matter experts (SMEs) in area of post-disaster recovery were asked to weight and rank identified PDRBs. The current research contributes to understanding how the post-disaster recovery barriers affect recovery process. The results of this research can help the stakeholders and policy-makers evaluate the policy post-disaster recovery barriers and achieve sustainable post-disaster recovery.
Comparative Analysis of Strengths and Limitations of Infrastructure Resilience Measurement Methods
Thahomina Jahan Nipa, Sharareh Kermanshachi
Ms. Thahomina Jahan Nipa, University of Texas at Arlington Dr. Sharareh Kermanshachi, University of Texas at Arlington (Presenter)
Since the beginning of the 21st century, experts have increasingly started using resilience analysis of infrastructures to assess damages and performance of infrastructures suffered by disturbing events like natural and/or man-made hazards. Resilience level of infrastructures almost always gets affected due to severe calamitous events whether they encounter visible damages or not. Researchers have developed several methods to define physical condition and/or performance deviations of affected infrastructure by measuring resilience and transportation sector incorporated these models only recently. There are very few studies focusing on comparative analysis based on the advantages and disadvantages of these developed models throughout the literature. Therefore, the aim of this paper is to identify frameworks and analyze them based on their applicability and dimensions. To fulfill this aim a thorough review of literature was conducted to establish definition of resilience concept and identify frameworks. Three resilience measuring models related to technical aspects of transportation infrastructure resilience namely Critical Infrastructure Resilience Decision Support System (CIR-DSS), Coxâ€™s proportional hazards regression model and resilience optimization model were identified to conduct a comparative analysis. Findings of this study will be of great help to researchers as well as to practitioners to adopt appropriate measurement on the severity of damages and identify proactive strategies reducing unintended consequences of disruptive events.
Resilient micropolitan areas in the face of economic shocks: An institutional perspective
Cristina Poleacovschi, Monica Haddad, David Peters
Dr. Cristina Poleacovschi, Iowa State University (Presenter) Dr. Monica Haddad Dr. David Peters
Micropolitan areas (between 10,000 and 50,000 people) may experience economic shocks, which threaten their vitality. Factors related to economic shocks can range from local companies leaving a town or national economic crises affecting local economies. This research seeks to identify why certain micropolitan areas recover from an economic shock using the perspective of local micropolitan institutions. Using a case study of one resilient micropolitan area in the Midwest, U.S., researchers have conducted twelve interviews with local stakeholders representing diverse for-profit and government institutions. A grounded theory approach allowed identifying social infrastructure, physical infrastructure, and institutional infrastructure as drivers to promote economic resilience. The research project contributes to a systems approach to city resilience, identifying a range of adaptive capacities for economic resilience such as the importance of infrastructure for business attractiveness, infrastructure for quality of life, and presence of cross-institutional coalitions. This research informs policy makers regarding the importance of a range of holistic factors which are likely to increase the adaptive capacity to economic shocks.
Robust Reserve Capacity Planning for Post-Disaster Health-care Facilities through Intelligent Planning Units (IPUs)
Juyeong Choi, Fehintola Sanusi, Makarand Hastak
Dr. Juyeong Choi, Department of Civil & Environmental Engineering at FAMU-FSU College of Engineering (Presenter) Ms. Fehintola Sanusi, Florida State University Dr. Makarand Hastak, Division of Construction Engineering and Management, Purdue University
Disasters often challenge the operation of health-care facilities. In particular, the insufficient supply of utility services and medical supplies can significantly compromise the operating capacities of hospitals without proper planning of reserve capacities (e.g., backup generators, bottled water, or a stockpile of emergency resources). This research employs the concept of intelligent planning units (IPUs) to guide health-care facilities on how to plan their reserve capacities in preparation for utility disruptions. The use of the IPUs enables resource planning at a single-patient care level based on the objective of a higher planning unit (e.g., service room level or hospital level). This research develops a mixed integer linear programming model that determines required reserve capacities for a post-disaster hospital to provide the highest level of care for patients (i.e., the objective of a high planning unit) through the optimization of the planning units for single-patient care within budget constraints. To demonstrate the implementation of the model, this study shows how to optimize the reserve capacities of a hypothetical hospital to operate intensive care unit services in two post-disaster scenarios: disruptions of water and power service. The recommended capacity plan based on the optimization model varies depending on a hospitalâ€™s budget constraints for planning and target quality of service; the higher the risk awareness and target level of medical services, the more expensive the recommended plan. As such, this model can help hospitals adjust and allocate budgets for mitigation planning depending on their desired level of resilience.
The Effect of Social Capital on Post-Disaster Informal Reconstruction in Puerto Rico
Jessica Talbot, Cristina Poleacovschi, Sara Hamideh
Ms. Jessica Talbot, Iowa State University (Presenter) Dr. Cristina Poleacovschi, Iowa State University Dr. Sara Hamideh, Iowa State University
Puerto Rico was devastated by Hurricanes Irma and Maria in September 2017. Housing became an immediate concern as the island experienced significant delays in response and recovery efforts. Thus, communities had to rely on their own resources to initiate the reconstruction process. This research defines these self-recovery actions as informal reconstruction, which represents the design and construction actions carried out by households in establishing temporary and permanent features of their houses outside of formal construction processes and regulations. While over 50% of houses in Puerto Rico have used these informal methods, there is limited understanding of the phenomenon and its drivers. This study addresses that gap by focusing on community drivers and asks the question, “What role does social capital play in the post-disaster informal reconstruction process?” The research uses social capital as the theoretical lens to understand how communities were able to mobilize their own resources and build informally during critical times. Social capital represents social ties between individuals and groups and is characterized by three distinct and important forms including bonding (close communities), bridging (horizontal relationships with other distinct communities) and linking (a vertical relationship with an established power dynamic). Data collection included surveys with 75 household owners in five rural communities (Adjuntas, Barranquitas, Yabucoa, Loiza and Culebra island) to measure levels of social capital and informal reconstruction. Data analysis included statistical analysis of surveys to identify the effect of different forms of social capital on informal reconstruction. Results showed that households reporting higher levels of social capital felt most empowered in the reconstruction process and on average participated in more reconstruction activities, and in a quicker time frame, than those reporting lower levels of social capital. Further, that bonding capital specifically, characterized by strong feelings of trust amongst neighbors and family members living in close proximity to each other, proved most effective for initiating informal reconstruction. This research contributes to social capital theory in post-disaster recovery by showing how different social capital forms work in complementary ways to mobilize resources for housing reconstruction. These results inform policy makers about community planning by identifying and emphasizing social characteristics which are essential in post-disaster recovery and long-term resilience.
Durability of Structures
Effect of superabsorbent polymer on mitigating damages at steel bar-concrete interface
Seyed Sina Mousavi Ojarestaghi, Claudiane Ouellet-Plamondon, Lotfi Guizani
Mr. Seyed Sina Mousavi Ojarestaghi, École de technologie supérieure (Presenter) Dr. Claudiane Ouellet-Plamondon, École de technologie supérieure Dr. Lotfi Guizani, École de technologie supérieure
Autogenous healing capacity of concrete has been considered in the last decades as a smart ability for mitigating internal damages in concrete structures. However, there is no specific research for healing cracks at rebar-concrete interfaces. Superabsorbent polymer (SAP) was used in this study inside the mixture to produce SAP concrete as a smart generation of concrete for autogenously healing cracks perpendicular to the rebar direction. An experimental program was conducted to check the performance of SAP as a healing agent in comparison with the reference mix. Two types of SAP particle sizes were considered and tested in this program with 0.25 %wt. of cement. Splitting test (Brazilian) was used to simulate pre-cracking at rebar-concrete interface. Controlled displacement loading with the rate of 0.15 mm/min was applied to prevent unexpected splitting failure during pre-cracking process. Although crack gauges were installed at both sided of specimens to control crack width limitation, ultimate crack width was measured directly after stopping the test. Two period of 14 and 28 days were considered for healing internal damages. Although bond strength is relatively lower in SAP-based concrete compared to the normal concrete because of macro pores at SAP locations, results show a good healing effect for initial bond strength, maximum bond strength, and energy absorbed by bond mechanism, within the cracks of cracked SAP-based concrete subjected to wet-dry recurring cycles. Results indicate that particle size of SAP has no significant effect on 28-day compressive strength and also rebar-concrete bond strength. Generally, findings evidently support the hypothesis that concrete composition could be a key parameter for controlling cracks at rebar-concrete interfacial surfaces. Obtained results show that concrete with SAP shows higher healing capacity compared to the concrete without SAP.
Measuring the Crack Width Change due to Self-healing on Concrete Surface Incorporating Different Minerals
Ahmed Suleiman, Moncef Nehdi
Mr. Ahmed Suleiman, University of Western Ontario (Presenter) Dr. Moncef Nehdi, Western University
In this study, the change in the surface crack width due to self-healing of concrete incorporating different minerals (i.e, fly ash (FA), metakaolin (MK), bentonite(BN), calcium carbonate (CC) and sodium bicarbonate(SBI) was investigated. Cement mortar specimens were prepared with the partial substitution of cement type 10 with each mineral. In addition, PVA fiber at a dosage of 1% by volume fraction was added to the mortar mixtures. At 28 days, all specimens were cracked by applying a tensile stress and then submerged in water to allow the development of self-healing of cracks. Change in crack width in each specimen due to the healing process was investigated using optical microscopy. Results showed that self-healing of surface cracks can be improved using minerals capable to promote further carbonation.
Numerical model of the chloride transport by capillarity effects in cement materials
Thomas Sanchez, David Conciatori , Francine LaferriÃ¨re
Dr. Thomas Sanchez, Laval University (Presenter) David Conciatori Dr. Francine Laferrière
Reinforced concrete infrastructure subjected to wet-dry cycles is deteriorating at an accelerated rate. The transport of chloride ions, responsible for the corrosion of the reinforcements in these materials, is not only due to diffusion but also to the effects of water transport and capillarity. These two last phenomena are currently very poorly modelled. This work therefore aims to create a numerical model of multi-species and reactive transport of chlorinated ions by capillarity in a cementitious material. The main difficulty encountered in measuring capillary suction is the great complexity of obtaining experimental data. Indeed, a capillary test only makes it possible to obtain the concentration of chloride that has penetrated after a certain time. It is then necessary to carry out several of them under the same experimental conditions to obtain an evolution of the penetration of chloride ions. This study is based on innovative experimental work recently carried out (Conciatori et al., 2010): capillary tests with a chloride sensor inserted inside the cementitious matrix to measure the evolution of chloride concentration over time at a given penetration depth. During this study, simulations with the TransChlor prediction software had been carried out but did not allow to accurately simulate the phenomena involved by the experimental curve. One possible explanation is that the software used is uni-species and does not consider chemical reactions in a phenomenological way.
In the proposed article, we thus created a numerical model under the PhreeqC multi-species reactive transport software capable of modelling chloride transport during a capillarity test by a Reactive, Advective and Dispersive law. The model considers the diffusion of chlorinated ions and water transport by capillarity, as well as the chemical reactions that occur between the ions and the cementitious matrix in a phenomenological way. In larger perspective, this study let to improve knowledge in concrete durability structures in severe environmental condition and the numerical model that can be created to predict their life service to better maintenance.
Conciatori, D., Laferrière, F., Brühwiler, E., 2010. Comprehensive modeling of chloride ion and water ingress into concrete considering thermal and carbonation state for real climate. Cem. Concr. Res. 40, 109–118. https://doi.org/10/bd9q4n
Relationships between free and water-soluble chloride concentrations in concrete
Mehdi Shafikhani, Samir Chidiac
Mr. Mehdi Shafikhani, McMaster University (Presenter) Dr. Samir Chidiac, McMaster University
Corrosion of metals embedded in concrete is pivotal when studying durability of reinforced concrete structures. Chloride ions present in the vicinity of steel reinforcements tend to initiate and/or accelerate their corrosion. Â Chloride ions are either bound physically or chemically to the cementing material or free in the pore solution, and only the latter can be transported. Free chloride concentration Cf was measured by pore solution expression method however it is found to be very difficult in low water to cement ratios. Water extraction method is used to measure water-soluble chloride concentration Cw in concrete, however the results are found to be highly depend on liquid to solid ratio, temperature, size of particles, and extraction method. The aim of this study is to experimentally evaluate current standard test methods, standard test method for acid-soluble chloride (ASTM C1152-04 ) and water-soluble chloride (ASTM C1218-15 ) in mortar and concrete, and the relationships between Cw and Cf.
Sixteen concrete mixes containing Portland-limestone (CSA type GUL) cement with and without supplementary cementing materials including silica fume and/or ground granulated blast-furnace slag were subjected to a non-steady state migration experiment. The acid-soluble and water-soluble chloride concentration at different layers of the samples were determined at 84 days based on ASTM C1152-04  and C1218-15  test methods, respectively. Freundlich isotherm was employed along with total chloride concentration data to determine free chloride Cf values. Linear relationships between Cw and Cf were observed with a significant dependence on binder composition.
Self-healing concrete: a critical review
Shannon Guo, Samir Chidiac
Ms. Shannon Guo, McMaster University (Presenter) Dr. Samir Chidiac, McMaster University
The need for sustainable concrete infrastructure is driving the development of smart structural materials. Inspired by the healing capabilities of living organisms, self-healing concrete utilizes a responsive healing system that closes cracks immediately when they form, effectively minimizing material deterioration, recovering durability and reducing the need for manual repair. One of the major categories of self-healing mechanisms is autonomous healing, which utilizes chemical, mineral, or bacterial healing agents that are not normally found in concrete. The healing agent is delivered via embedded vessels in the form of a continuous tubular network or as discrete microcapsules dispersed throughout the concrete. When concrete cracks, the vessel breaks and releases the reservoir of healing material into the crack, which effectively seals the crack and prevents further crack propagation. This study reviews the state-of-art pertaining to autonomous self-healing of concrete. This includes the material and manufacturing technologies and the efficiency of the self-healing systems. The healing effectiveness of the healing system is evaluated through the recovery of concrete mechanical properties and durability. The limitations and potentials of the proposed autonomous self-healing systems are discussed.
State-of-the-Art on the Combined Effects of Freeze/Thaw Exposure and Reinforcement Corrosion on the Structural Performance of RC Structures
Maha Dabas, Beatriz Martin-Perez, Husham Almansour
Mrs. Maha Dabas, University of Ottawa (Presenter) Dr. Beatriz Martin-Perez, University of Ottawa Dr. Husham Almansour, NRC Canada
State-of-the-Art on the Combined Effects of Freeze/Thaw Exposure and Reinforcement Corrosion on the Structural Performance of RC Structures
Maha Dabas, Ph.D. Candidate, Dept. of Civil Engineering,
University of Ottawa, Ottawa, ON, Canada, email@example.com
Beatriz Martín-Pérez, Associate Professor, Dept. of Civil Engineering,
University of Ottawa, Ottawa, ON, Canada, firstname.lastname@example.org
Husham Almansour, Senior Research Officer, Civil Engineering Infrastructure,
National Research Council Canada, Ottawa, ON, Canada, Husham.email@example.com
Freezing & Thawing Cycles (FTC) on Reinforced Concrete (RC) structures is a significant problem for vulnerable infrastructure exposed to extreme climate conditions. This problem is exacerbated by the presence of de-icing agents that lead to reinforcement corrosion and overall concrete deterioration. Current research has mainly focused on studying the mechanical properties of concrete when exposed to cyclic conditions of freeze & thaw. Few studies have analyzed the influence of FTC on the structural performance of RC structures or the dual action of FTC and reinforcement corrosion on the structural performance of RC structural members. This paper surveys available literature on the synergistic effects of one or multiple environmental exposures on the durability and structural performance of concrete structures subjected to service loads. It also provides a summary comparison between adopted test methodologies according to current national and international standards. The literature survey is organized as follows: the 1) effect of FTC on: i) mechanical properties; and ii) structural performance; 2) the effect of dual action of FTC and corrosion on the mechanical properties and structural performance of concrete; and, 3) a comparison summary of the methodologies implemented by previous studies according to current international standards. Finally, this paper draws a series of conclusions and recommendations for future work based on the reviewed literature.
Dynamics of structures
Hindcasting the damage of Ottawa-Gatineau, Ontario tornado outbreak of September 2018: coupled computational fluid dynamics and finite element analysis approach
Impact Response of Falling Object Protective Structures (FOPS)
Helmut M. Haydl
This paper examines the effects of falling objects impacting on protective structures in the mining industry. The impact problem is defined in terms of the equality betwen impact energy and work energy dissipation of the structure. To obtain realistic results from the mathematical structural model, the assumption is made that the impact energy is distributed to all members that experience deformation from the impact. The distribution of the impact energy to the structural members is taken as proportional to the force that causes the deflection in the member during impact. A simple mathematical procedure to estimate both elastic and rigid-plastic response of the structural members is presented. The problems encountered in defining the impact energy and a design criteria are discussed. Numerical examples are worked out to illustrate the mathematical procedures.
Lightweight Pedestrian Bridges: Evaluation and Calibration of Design Standards for Vibration Serviceability
Pampa Dey, Sriram Narasimhan, Scott Walbridge
Dr. Pampa Dey, Laval University (Presenter) Mr. Sriram Narasimhan, University of Waterloo Dr. Scott Walbridge, University of Waterloo
The rapid advancement in material technology has paved the way for various lightweight yet highly durable materials such as aluminum with low maintenance cost, providing the construction industry with a fascinating opportunity to build lightweight and architecturally appealing pedestrian bridges. Nevertheless, this has resulted in lively bridges, which often suffer excessive vibrations leading to serviceability problems under pedestrian-induced walking loads. Various design standards have been developed for serviceability design of these structures, however primarily based on observations from low frequency bridges. These standards have neglected the altered mass-stiffness relationship for structures with lightweight material, which causes higher frequency but large amount of vibration magnitude. Hence, it is imperative to evaluate the existing design standards for lightweight bridges, especially using experimental observations. Another central issue in the design process by these standards is proper consideration and treatment of the large uncertainty in the loadings and the complex behavior of the pedestrians to bridge response. This study has underscored these discrepancies in the bridge standards through a coupled experimental and analytical investigation on aluminum pedestrian bridges under walking loads. The experimental results from two full-scale aluminum bridges show significant differences in the predicted responses by the design load models as compared to the measurements. The key parameters employed in the design equations, such as dynamic load factors, walking speed, and multiplication factors, are identified as primary reasons for this disagreement. Accordingly, modifications have been recommended to better align the predictions with experimental test results, which also harmonize these standards amongst each other. In addition, a reliability-based evaluation is carried out on code-compliant bridges by incorporating the uncertainties associated with various parameters in the design process. Based on the evaluation results, the design equations are calibrated for higher reliability indices and partial factors for the calibrated design equation are estimated. For economic designs, userâ€™s comfort limits based on the frequency of occurrence of the traffic event and the class of pedestrian bridge are adopted during the calibration process. The calibrated design standards ensure acceptable performance during both design and non-frequent heavy traffic loading events, while at the same time yielding economic designs.
Seismic Collapse Safety Assessment of Concrete Beam Column Joints Reinforced with Different Shape Memory Alloy Rebars
AHM Muntasir Billah, Mumtasirun Nahar
Dr. AHM Muntasir Billah, Lakehead University (Presenter) Mrs. Mumtasirun Nahar, Military Institute of Science and Technology
In recent years, shape memory alloy (SMA) have drawn significant attention and interests among researchers and structural engineers for diverse civil engineering applications. Superelasticity, shape memory effect, and hysteretic damping, are the three major attributes of SMAs that make them ideally suited for applications in concrete frames. Among different compositions of SMA, Nickel-Titanium (NiTi) SMA has gained much attention for its superior mechanical and thermal performance over other compositions. However, the high cost and low machinability restricts the widespread use of NiTi SMAs in structural applications. Recently, several compositions of SMAs have been developed, such as Fe-based and Cu-based SMAs, which offer significantly lower cost and superior machinability compared to commonly used NiTi SMAs. The objective of this study is to evaluate the comparative seismic collapse safety of concrete beam-column joints reinforced with five different SMAs. The beam-column joint is assumed to be part of a seven storey moment resistant frame building located in Dhaka, Bangladesh. Fragility analysis will be conducted considering uncertainty in the material properties and as well the seismic hazard of the site location. A total of 20 near fault and far field ground motions will be considered for developing the collapse fragility curves. The collapse vulnerability of the five different SMA-RC beam-column joints will be evaluated interms of maximum inter-storey drift as the demand parameter as well as through development of collapse margin ratios.
VIBRATION-BASED SYSTEM IDENTIFICATION OF A REINFORCED CONCRETE SHEAR WALL USING FREQUENCY DOMAIN METHODS
Timir Baran Roy, Soraj Kumar Panigrahi, Ajay Chourasia, Lucia Tirca, Ashutosh Bagchi
Mr. Timir Baran Roy, Concordia University (Presenter) Dr. Soraj Kumar Panigrahi, CSIR-Central Building Research Institute, Roorkee, India Dr. Ajay Chourasia, CSIR-Central Building Research Institute, Roorkee, India Dr. Lucia Tirca, Concordia University, Canada Dr. Ashutosh Bagchi, Concordia University, Canada
In last few decades, vibration-based Structural Health Monitoring (SHM) has played a significant role to study different parameters of a structure. Frequency Domain Decomposition (FDD) and Stochastic Subspace Identification (SSI) play important roles to identify system properties, such as: modal frequencies, mode shape and damping ratio. The focus of the present research is to identify modal frequencies of a scaled down RC shear wall in laboratory conditions using wired PCB Piezotronics sensor network. For signal decomposition, FDD has been utilized to get modal frequencies of the experimental shear wall using ambient vibration data. Validation of the results obtained from the signal processing was performed through analytical modeling. From the analysis results, different modal frequencies are obtained at different phase of the experiment.
CONSTRUCTION COST INCREASE A SOURCE FOR UNAFFORDABLE HOUSING DELIVERY IN THE CITIES OF DEVELOPING NATIONS
The majority of construction industries in developing nations are challenged with a high cost of construction in the delivery of housing, nevertheless, the incompetence of construction operators in the management of client briefing toward achieving cost-efficient design practices is an additional problem. Thus, the low-income earners perceive affordable housing a phantasm, thereafter, living in the slums and squatters were social crimes are invented. This practice continues increases on daily bases without restrained. Based on this assertion, demand the most important reason to investigate construction cost increase a source for unaffordable housing delivery in the cities. The objectives of this study are to establish the techniques that will restraint construction cost within budgeted cost in order to deliver inexpensive housing for poor residents in the cities. The methodology used to achieve the aim and objective of this study is a sequential mixed method that involved quantitative and qualitative techniques, questionnaires were administered to the architects, contractors, project managers, quantity surveyors, site engineers, and contract managers. Questions related to their knowledge of construction cost increase a source for unaffordable housing delivery in the cities. Data collected were analysed using SPSS software that contains a descriptive statistical and principal component analysis (PCA) and the results obtained were validated using a qualitative process. The most influential techniques that will restraint construction cost within the initial budgeted cost are; establishment of contract management procedures initiated on site; adequate coordination of client briefing phase and transition to design phase through to construction stage; adequate establishment of client objectives through to implementation will reduce frequent alteration of drawings; constant promoting high standard design and implementation among professionals; adequate planning for the management of construction resources usage; and satisfactory planning for resources waste reduction during production. The deliberation of these identified techniques with client briefing on the aim and objectives of the proposed project will reduce frequent alteration of drawings and enhance the adequate planning for high standard design and implementation among professionals. Consequently, the established factors of techniques for construction operators will make housing constantly available at a cost within the reach of lower income earners.
Keywords; Construction cost; Cities; Developing nations; Housing delivery and Unaffordable
Evaluating Design Solutions for Cycle Tracks along Urban Arterial Roads
Michael Bandiera, Clayton D'Souza, Daniel Gaglia, Daniel Henrique, Said Easa, Mladen Mladenov, Michael O'Donnell
Mr. Michael Bandiera, Ryerson University Mr. Clayton D'Souza, Ryerson University Mr. Daniel Gaglia, Ryerson University Mr. Daniel Henrique, Ryerson University (Presenter) Dr. Said Easa, Ryerson University, Canada Mr. Mladen Mladenov, Ryerson University Mr. Michael O'Donnell, Ryerson University
Many arterial roadways in urban areas justifiably focus on motor vehicle traffic, but unfortunately they are not very accommodating to other modes of transportation, specifically cycling. Providing a safe and comfortable route for cyclists is key to encouraging cycling as a mode of transportation, however it must be balanced with accommodating the high volume of motor vehicles present. This is an issue mainly affecting urban areas in Europe and North America.
The purpose of this study is to design a dedicated bicycle facility along University Avenue, a major north-south arterial road in Torontoâ€™s downtown core. The area of evaluation encompasses Front Street West and College Street, which is a span of approximately 1.9 km. In this study, case studies on bicycle facilities in many cities, most notably Amsterdam, Copenhagen, Minneapolis, Montreal, Portland, and Vancouver were analyzed to determine the specific designs and practices that could be potentially applicable in Toronto. The study evaluated the performance of two common design alternatives for bicycle facilities along University Avenue in Toronto. The alternatives included a separated one-way cycle track and a raised cycle track. Both design types were open to new innovations specific to the University Avenue corridor, provided that they meet municipal and provincial standards. The two alternatives were evaluated using a unique weighted scoring method that involved safety, economic, level of service, and constructability. A recommendation has been made to further evaluate the separated one-way cycle track for the given stretch of road.
The goal of this study is to establish a set of practical design guidelines and evaluation methods for bicycle facilities on major arterial roads in urban settings, and to encourage further research into the topic.
Factors Affecting Bid Let Dates and Construction Payout Curves on Transportation Mega Projects
William Rasdorf, Abdullah Alsharef, Min Liu, Edward Jaselskis, Frank Bowen, Majed Al-Ghandour, Larry Goode
Mr. William Rasdorf, North Carolina State University Mr. Abdullah Alsharef, North Carolina State University Ms. Min Liu Dr. Edward Jaselskis, North Carolina State University (Presenter) Mr. Frank Bowen Mr. Majed Al-Ghandour, North Carolina Department of Transportation Mr. Larry Goode , North Carolina State University
North Carolina Department of Transportation (NCDOT) projects with construction costs of $50 million or more, known as mega projects, make up more than 50% of their total construction expenditures while representing less than 10% of the total project count. The estimated let dates and construction expenditures for these projects can vary significantly. This paper identifies two ways of monitoring mega projects to quickly recognize and mitigate developing problems. The research methodology included an extensive literature review and interviews with 23 agency subject matter experts and construction contractors. The paper contributes to the body of knowledge through collecting and analyzing data pertaining to strategic milestones and expenditure payouts for transportation mega projects. The paper also contributes a new checklist that enables agencies to identifying projects that are at risk of let delays during preconstruction and a new approach for identify projects that are not meeting their original construction performance baseline goals (and require intervention for corrective action) during construction, both of which can result in costly delays.
Life-cycle Assessment of Full-scale Membrane Bioreactor and Tertiary Treatment Technologies in Fruit Processing Industry
Tong Chu, Richard Zytner, Bassim Abbassi
Mr. Tong Chu, University of Guelph (Presenter) Dr. Richard Zytner, School of Engineering, University of Guelph Dr. Bassim Abbassi, University of Guelph
Fruit processing sector is one of the major water-consuming industries. Large amounts of wastewater is discharged by fruit processors containing high biological oxygen demand (BOD), total suspended solids (TSS), total nitrogen (TN) and total phosphorus (TP). If not properly treated, the receiving waters will be contaminated with the risk of eutrophication. Membrane bioreactor (MBR) is a feasible technology for treating the fruit processing wastewater, and when combined with tertiary treatment technology such as reverse osmosis (RO), water reuse is possible. The objective of this study is to quantitively analyze the total environmental benefits and impacts of the wastewater treatment technologies in fruit processing sector, comparing the impacts of different treatment options, including discharge without treatment. The quantitative metrics will show others users the benefits of being environmentally proactive.Â
The environmental assessment will be achieved by conducting a life-cycle assessment (LCA) under the guideline of ISO 14040, the international standard for life-cycle assessment. The software SimaPro 22.214.171.124 is applied for the LCA study and two methods are chosen for quantifying the life-cycle impact results, namely ReCiPe v1.11 and TRACI v2.1. Three scenarios are defined for the assessment: (1) no treatment; (2) MBR; (3) MBR + RO + UV. The life-cycle inventory is developed based on professional databases and a full-scale wastewater treatment facility in a fruit industry located in Ontario. The early results include a cradle-to-grave inventory throughout the life-cycle of each scenario, including raw material acquisition, component production, use, end-of-life treatment, and final disposal. Further analysis is ongoing to determine the life-cycle impact assessment and to quantify the environmental impacts of each scenario and a comparison among the treatment options. The completed paper will show scientific evidence for all stakeholders in the fruit processing sector on how to optimize their treatment options and make informed policy decisions.
Problem Based Learning for reinforcing Engineering Education in the Universities of Technologies in South Africa
Dillip Das, Yali Woyessa
Dr. Dillip Das, Central University of Technology, Free State (Presenter) Ms. Yali Woyessa, Central University of Technology, Free State
Universities of Technologies (UoT) in South Africa generally follow Outcomes Based Education (OBE) in which Work Integrated Learning (WIL) is an indispensable element. However, in the recent re-curriculation and adoption of new qualifications both at the Diploma and Bachelors level in Engineering and Technology education, the WIL component is not anymore compulsory to obtain a qualification. So, the students may not have any work place training or experience during their study, which may put them at risk with regards to obtain the requisite graduate attributes of applying the knowledge, analysing, designing or problem solving and become industry relevant. Problem Based Learning (PBL) is argued to offer the opportunities of hands on experience on practical problem solving within an academic environment, which could suffice to the needs of the students to become industry relevant. Therefore, the objective of this study is to examine the relevancy and implications of the PBL in Engineering Education and the process of its integration in under graduate engineering programmes in the UoTs of South Africa. The study largely relied on the lessons learned from the industry based PBL workshops conducted by considering undergraduate engineering students including that of civil engineering and problems related to Sustainable Development Goals (SDG) of the United Nations. Also, a survey was conducted to collect data from the participants in the workshop. Also, a focus group discussion was conducted. Quantitative statistical analyses of data collected and qualitative narrative analysis of the perceptions of the stakeholders and content analyses of the student projects conducted during the workshops were conducted. Findings suggest that although it was contextualised in a controlled academic environment, PBL is relevant to engineering students as it provided them the opportunity to deal with practical problems with the assistance of both academicians and industry partners. Also, it is found that it was acceptable, created an environment for constructive engagement among the students and teachers, and provided freedom to analyse the situation, apply knowledge and explore innovation in the problem solving. In other words, it reinforced the student learning through the hands on exercise on the projects they conducted and explore engineering solutions. Further, this paper argues that PBL can reinforce the student learning if it can be integrated to the learning programmes through aligning the student projects or assignments with industry problems as well as aligning them constructively in terms of Intended Learning Outcomes, teaching and learning activities and assessment tasks.
Water Distribution Systems: Effect of Geographical Location on Expert Judgement
Zahra Zangenehmadar, Sasan Golnaraghi, Seyedeh Sara Fanaei
Dr. Zahra Zangenehmadar, Concordia University (Presenter) Mr. Sasan Golnaraghi, Concordia University Mrs. Seyedeh Sara Fanaei
Water distribution systems are one of the key elements in the underground infrastructure network. There are large numbers of studies on the various aspects of deterioration, failure, rehabilitation and replacement of water pipelines in which certain factors, along with their weights of importance, are assumed to influence the performance of water distribution pipelines. These weights of importance are mostly calculated based on expert judgement which is shaped by years of experience and the demographic distribution of experts. Since these factors will be used in the performance prediction of the pipelines, the accuracy of these models will be highly dependent on the experts’ opinions. This study aims to evaluate the impact of location on expert judgement in performance assessment of water distribution networks. Two groups of professionals with the same set of circumstances from Canada and Qatar have been chosen to determine the influence of location on decision-making. The same set of questionnaires was sent to both groups asking them to identify the most important factors in the deterioration of water pipelines and their respective weights of importance. Results show that the experts’ opinions are greatly colored by their location and the surrounding environment, which highlights the importance of considering these factors in further studies.
Arsenic bioremediation: Importance of sample preparation for environmental arsenic species identification.
Saif Rafi, Kerry McPhedran, Ali Motalebi Damuchali, Aslan Hwanhwi Lee, Wonjae Chang, Raquibul Alam
Mr. Saif Rafi, University of Saskatchewan (Presenter) Dr. Kerry McPhedran, University of Saskatchewan Dr. Ali Motalebi Damuchali Dr. Aslan Hwanhwi Lee, University of Saskatchewan Dr. Wonjae Chang, University of Saskatchewan Dr. Raquibul Alam
Industrial development and increasing anthropogenic activities such as mining continue to be of concern as they lead topollution of waters. Mine wastes contain heavy metals, such as arsenic, that can contaminate surface waters and groundwater. Arsenic is found in four oxidation states in species including inorganic and organic compounds that are dependent on the existence of sorbent materials, pH, redox potential, and microbial metabolic activity. The As(III)/As(V) states dominate in water given their solubility’s with As(III) being 10 times more toxic than As(V). Thus, knowing the specific arsenic species in wastes is important for understanding both their toxicity potential and for development of specific treatment technologies. The problem with determining arsenic speciation is the need for advanced analytical instruments for the analysis that are not readily available. Thus, suitable sample processing and storage procedures are vital to preserve the species from the time of sampling to analysis. Currently, we used three methods for preservation including: (1)no acid; (2)ethylene diaminete tetra acetic acid (EDTA); and (3) 2% nitric acid (HNO3). The overall objective of our research program is to investigate and mitigate arsenic from mine waste rock that will be stored in water in Saskatchewan, Canada, withfocus on bioremediation of arsenic at relevant in situ temperatures. Thus, the samples preserved we taken from these experimental reactors for the current study. Overall, the no acid treatment resulted in the most consistent speciation preservation for experimental samples. Interestingly, both standard method acid treatments resulted in unexpected oxidation of arsenic.
Central Composite Design for Optimizing Derivatization of Metformin and Guanylurea in Water Samples Detected by Gas Chromatography - Mass Spectrometry
Yunwen Tao, Baiyu (Helen) Zhang, Bing Chen
Ms. Yunwen Tao, Memorial University of Newfoundland (Presenter) Dr. Baiyu (Helen) Zhang, Memorial University Dr. Bing Chen, Memorial University
Authors: Yunwen Tao, Baiyu Zhang, Bing Chen
Abstract: Emerging pollutants (EPs) are chemicals produced by human and industrial activities such as pharmaceuticals. Metformin, a widely used first-line oral drug for type 2 diabetes, is difficult to be metabolized inside the human body and thus becomes an emerging environmental contaminant with growing concerns. Guanylurea is metformin’s biotransformation product. To help better track the occurrence of the two compounds in the environments, the improvement of methods for metformin and guanylurea analysis is necessary. Derivatization of metformin and guanylurea is the key pre-treatment procedure before the analysis of metformin and guanylurea by gas chromatography-mass spectrometry (GC-MS). Central Composite design (CCD), a statistical design of experiments (DOE) methodology, was applied to identify the impact of factors affecting the derivatization reactions of metformin and guanylurea. The four factors included within the CCD modelling are temperature (70-90ºC), reacting time (40-70minutes), solvent (acetonitrile, 1,4-dioxane), and ratio (0.5-1.5:1) of reagent to target component. Buformin and N-methyl-bis(trifluoroacetamide) were used as the internal standard and derivatization reagent, respectively. The optimal conditions for enhancing the sensitization of metformin and guanylurea derivatization performance were obtained.
Impact of Climate Change on Dissolved Oxygen Concentrations and on Waste Allocation Plan of Nile River in Egypt
Rawnaa Yassin , Sherine Elbaradei
Ms. Rawnaa Yassin , American University in Cairo (Presenter) Dr. Sherine Elbaradei, American University and Nile University
Global warming affects many aspects of life thus affecting ecosystem and water quality in rivers. This research investigates the impact of global warming on dissolved oxygen (DO) concentrations in Nile river. The study is done on Nile River in Egypt at three monitoring stations
A mathematical model was developed to predict air temperatures from 2013 till 2030 and hence predict values of water temperatures and resulting DO concentrations. Furthermore, the effect of global warming on locations of water and waste water treatment plants on river Nile was studied. The study investigated temperatures and DO values in summer (peak discharge of Nile River In Egypt) and in winter (lowest discharge in the Nile in Egypt)
It was found that values of critical DO concentrations were negatively impacted and thus decreased over the years according to the global warming effects by the following amounts: at Luxor 3.99% in February and 4.26 % in August, at Cairo 4% in February and 4.8% in August and at Alexandria 1.34% in February and 5.16% in August. Furthermore, global warming has a considerable effect on locations of water and waste water treatment plants on rivers and thus on the waste allocation plan.
Keywords: global warming, dissolved oxygen concentration, rivers, water quality, water quality odeling, waste allocation, water treatmet plant, waste water treatment plant.
Intersectoral Water Allocation Using AN Input-Output Model
Hamid Abdolabadi, Amin Sarang, John Little, Barbara Jean Lence
Dr. Hamid Abdolabadi Dr. Amin Sarang, University of Tehran (Presenter) Dr. John Little, Virginia Tech Dr. Barbara Jean Lence
An input-output model allows the interaction between the supply and demand sides of an economy to be examined. It can also provide decision makers with information on the total production of sectors as well as required resources. In this paper, we used an input-output model to manage water use and estimate the total water use for various economic sectors in Iran's North Khorasan Province (INKP). Initially, the province's economy was disaggregated into 19 sectors and the regional input-output table was estimated using the Cross-hauling Adjusted Regionalization Method. Then, using linear programming, the basic input-output model was transformed into an improved input-output model having the ability to choose among alternative technologies for allocating water to sectors. To compensate for the water shortage by selecting alternative technologies and assessing their impact on the total cost of the system as well as the production, three scenarios for managing the supply side and one scenario for reducing the final demand of the most water-consuming sector (managing the demand side) were analyzed. The results showed that the agriculture sector is always required to use less water-consuming and more expensive technology to compensate for about 161 million cubic meters of water to keep the total production unchanged.
Mineralization pathways and kinetics of degradation of emerging contaminants as mixtures using UV/H2O2
Jordan Hollman, John Albino Dominic, Gopal Achari, Joo-Hwa Tay
Mr. Jordan Hollman, University of Calgary (Presenter) Dr. John Albino Dominic, University of Calgary Dr. Gopal Achari, University of Calgary Dr. Joo-Hwa Tay, University of Calgary
The removal of pharmaceuticals from water and wastewater is an emerging concern due to a myriad of potential negative impacts posed on ecosystem and human health. A need exists to advance current wastewater/water treatment technologies to remove pharmaceuticals from water, along with a more robust understanding of the underlying chemistry of the processes. Amongst existing technologies, advanced oxidation processes (AOPs) have very high potential as they can degrade pharmaceuticals without creating additional waste streams. AOPs produce highly reactive hydroxy radicals which are non-specific in attach and can degrade a large variety of pollutants including pharmaceuticals. UV/H2O2 was the AOP used in this study as it could be implemented into existing wastewater treatment plants with minimal modification. The work presented here focused on degradation of four pharmaceuticals in a mixture: sulfamethoxazole (an antibiotic), venlafaxine (an antidepressant), carbamazepine (an anticonvulsant) and fluoxetine (an antidepressant) using UV/H2O2. Working with mixtures is a frequently understudied aspect of research on micropollutants but is essential for a working full-scale process as individual compounds are never found in isolation in water or wastewater. Degradation of a single compound by UV/H2O2 in comparison with mixture of compounds showed a significantly reduced rate of degradation, indicating that the presence of co-contaminants can be a significant limiting factor in degradation. The degradation of all four compounds was observed to follow pseudo first order kinetics with rates varying between each compound. The molecular structure and functional groups present in each pharmaceutical compound play a major role in susceptibility of each compound for degradation by hydroxyl radicals. Each reaction was studied in detail to make a prediction of the most likely degradation pathway for each compound. Additionally, a parametric study of H2O2 dose was conducted on the pharmaceutical mixture, which indicated that increasing H2O2 dosage can increase degradation rate. However, at higher H2O2 doses, diminished returns on degradation rate are gained per mass of H2O2, making higher H2O2 dosages less economical for large scale application.
The Meewasin Northeast Swale: Using Natural Capital Asset Valuation to Value Saskatoonâ€™s Natural Resources
Scott Read, Kerry McPhedran
Mr. Scott Read, University of Saskatchewan (Presenter) Dr. Kerry McPhedran, University of Saskatchewan
The Meewasin Northeast Swale (Swale) is a 26-kilometre long, 2,800-hectare span of ancient prairie, riparian, forest, and wetland located partly in northeastern Saskatoon, Saskatchewan. Ancient grasslands and wetlands are endangered ecosystems and home to a wealth of biodiversity, yet this geologically & ecologically unique ecosystem is threatened by urban development including encroaching subdivisions and bisecting roadways, among others. Despite these threats to the Swale’s health, no substantial environmental impact monitoring has been done for the Swale. Additionally, the full value of the Swale – in terms of economic, sociocultural, and environmental value – is not fully accounted for. The City of Saskatoon neither understands the impacts the City is having on the Swale, nor appreciates the value the Swale provides to the community.
To rectify this knowledge gap, a natural capital asset valuation (NCAV) has been conducted for the Swale. NCAV is the process of determining the worth of an ecosystem and its services. The Swale's natural capital – its geography, soil, air, water, and living organisms – contributes ecosystem services: natural processes which benefit people. The NCAV for the Swale involves a combination of two non-market valuation techniques: replacement cost analysis and contingent valuation. Replacement cost analysis uses the cost of replacing an ecosystem service with a human-made equivalent as an analogue for ecosystem value. For the Swale, replacement cost analysis was applied to ecosystem services including flood & drought mitigation, water treatment, and carbon sequestration. Contingent valuation is a stated preference method of valuation in which the public is asked how much money they would be willing to pay to preserve an environmental feature such as sense of place, biodiversity, or aesthetics. A survey was developed and distributed throughout Saskatoon in partnership with the City of Saskatoon and Meewasin to determine the willingness-to-pay for environmental features.
The valuation of the Swale allows its stakeholders and managers to make enlightened management decisions. The NCAV methodology that has been developed is a framework, ready to be applied to other natural resources in Saskatoon and is meant to be adaptable to other municipalities in Canada. NCAV enhances the appreciation of capital – natural, human, and manufactured – allowing for responsible environmental decision making that balances economic, sociocultural, and environmental sustainability.
USE OF NON-WOVEN GEOTEXTILES FOR IMPROVING WATER QUALITY OF A EUTROPHIC LAKE: AN IN-SITU STUDY
Dileep Palakkeel Veetil, Catherine Mulligan, Mina Ghasri, Sam Bhat
Dr. Dileep Palakkeel Veetil, Concordia University (Presenter) Dr. Catherine Mulligan, Concordia University Ms. Mina Ghasri, Concordia University Mr. Sam Bhat, Titan Environmental Containment
Abstract: Lakes are an integral part of the freshwater resources in Quebec and their protection is very important as any impairment in the lake water quality can affect the publicâ€™s health and aquatic life. Lake Caron, a shallow eutrophic lake located in the Sainte-Anne-des-Lacs municipality in Quebec, has been under swimming advisory for many years due to algal blooms every summer. In this present study, a floating filtration unit with a sand prefilter and non-woven geotextile filter media, was tested to improve the lake water quality in a small area of the lake enclosed by a turbidity curtain. The water quality was monitored during the test by deploying two YSI-EXO2 probes in and out of the curtain and analysing water samples for total phosphorus, COD, turbidity, and total suspended solids. The geotextile filters together with the sand filter were effective for removing algae and suspended particles. Overall the filtration resulted in 78% total suspended solids, 39% total phosphorus and 53 % chlorophyll a removal in the contained lake water. Use of the pre-sand filtration allowed removal of large size particles and thus reduced rapid clogging of geotextiles.
Key Words: Blue green algae, Non-woven geotextiles, Filtration, Suspended Solids, Total Phosphorus
Water, Wastewater Management & Biochemical Impact of Sludge on Soil Properties In Port Harcourt, Rivers State, Nigeria
This paper presents an overview about water, wastewater management and biochemical impact of sludge on soil properties in Port Harcourt, which comprises of Port Harcourt City and Obio/Akpor Local Government Areas. The main problems related to the availability of water resources and their preservation from the pollution are described. Moreover, a detailed description of the different efforts done in Port Harcourt in recent years to overcome the technical, economical and organizational problems of water and wastewater management and to catch up the considerable delay regarding sanitation and recovery of treated wastewaters has been reported too. Such as the establishment of Port Harcourt Water and Sewage Corporation with the aim of providing, regulatory, adequate water resources infrastructure and affordable water supply for the growing population and sewage treatment. The use of Sequencing Batch Reactor (SBR) method is considered as the most appropriate and suitable treatment mechanism to treat the increasing flows of domestic wastewater in Port Harcourt. However, the effluent produced were up to standard as recommended by National Environmental Standards and Regulation Enforcement Agency (NESREA) and World Bank. Also is the establishment of the usefulness of the sludge in the production of fertilizer that is use for the improvement of the soil properties to enhance high agricultural productivity. This was done through the investigation of the biochemical such as Nitrogen(N), Phosphorous(P), Potassium(K) and TOM (Total Organic Matters) levels for the test soil (2.37 mg/kg, 32.89 mg/kg, 32.15 mg/kg, and 3.12 mg/kg) respectively over the control (0.93 mg/kg, 11.09 mg/kg, 36.35 mg/kg, and 2.14 mg/kg) respectively. Zn, Pb, Ni and TOC (Total Organic Carbon) which are essential to plants and animals were also found to be significantly higher in the test soil (19.26 mg/kg, 5.71 mg/kg, 1.60 mg/kg, and 1.81 mg/kg) respectively over the control (8.62 mg/kg, 2.58 mg/kg, 0.52 mg/kg, and 1.24 mg/kg) respectively
Erosion and Scour
A Hydrologic Model to Estimate Delta Water Availability in Alberta
Zahidul Islam, Michael Seneka, Joey Hurley, Shoma Tanzeeba
Dr. Zahidul Islam, Alberta Environment and Parks (Presenter) Mr. Michael Seneka, Alberta Environment and Parks Ms. Joey Hurley, Government of Alberta, Department of Environment and Parks Ms. Shoma Tanzeeba, Government of Alberta, Department of Environment and Parks
‘Delta Water’ is defined as the excess stormwater runoff generated from the increase in impervious surfaces associated with urban development. When allocated sustainably, stormwater use can offset potable water use and augment traditional water supplies. Albertans recognize the value in previously undervalued resources such as wastewater and stormwater. As a result, the Government of Alberta is exploring ways enable access to these alternative sources in a way that is protective of public and environmental health. For stormwater allocation purposes, this includes understanding the volumes of runoff generated as a result of urban development. A consistent and scientifically defensible approach is required to support decision making under Alberta’s regulatory framework for water management. In support of this policy initiative, we developed a hydrologic model to estimate delta water availability in Alberta. The spatial and temporal scale of the model has been chosen in such a way that the model can be applicable province-wide in a township scale (100 km2) as well as in a project scale (1-10 km2), and can provide delta water assessments based on long term historical climate data. Moreover, the model structure has been designed in such a way that balances the model implementation complexity with the scientific integrity. We have used the daily gridded climate dataset (1955-2016) from Alberta Climate Information Service, wall- to-wall landcover dataset (2010) from Alberta Biodiversity Monitoring Institute, and the soil texture data from Harmonized World Soil Database to prepare the model baseline scenario (pre-development). The hydrologic model includes Degree-Day snowmelt model, Morton’s evapotranspiration model, and SCS Runoff Curve Number model to simulate the pre-development surface runoff in a daily scale. The simulated daily runoff is then converted into long term mean annual runoff and calibrated against historical mean annual runoff at a township scale. The model has the ability to input the post-development landcover (for example, converting agricultural land or grassland into urban developments), re-generate the long term mean annual runoff due to landcover changes, and simulate the long term mean delta water in a township or project scale. We have tested the model at township scales province-wide, and also applied it for project case studies. Once the policy approved, applicants and regulators alike will have access to the final model, creating a transparent regulatory decision making process.
Integrating climate change in the evaluation of hydroelectric asset value
Richard Arsenault, Katherine Pineault, Ã‰lyse Fournier, Alexis Hannart, Annabelle Lamy
Mr. Richard Arsenault, École de technologie supérieure (Presenter) Mrs. Katherine Pineault, Ouranos Mrs. Élyse Fournier, Ouranos Dr. Alexis Hannart, Ouranos Mrs. Annabelle Lamy, Ouranos
Hydroelectric asset owners and managers, as well as other stakeholders, take financial and economic decisions based on the evaluation of their asset values. Amongst other factors, the value of hydroelectric assets depends upon their productivity and investments needed to maintain their integrity, safety and adaptability. Climate change may have an impact at both levels, as it will modify water supplies around the globe.
To date, it appears that the impacts of climate change on water supplies are rarely considered in the evaluation of hydroelectric asset values. In cases where it is, the methodologies used are specific to each analyst or organisation and are not based on comprehensive and peer-reviewed methods or recommended guidelines. The lack of recognised methodologies may lead to suboptimal investment decisions and may lead to maladaptation to climate change.
Ouranos, with the support and funding from Natural Resources Canada, Manitoba Hydro, Ontario Power Generation, Innergex, Brookfield Energy and Hydro-Quebec, aims to provide and disseminate a methodological framework to include climate change information in the evaluation of hydroelectric asset values. The co-construction of the framework with practitioners of the hydroelectric industry is central to the project. The framework must take into account real-life constraints, such as schedules, availability of data and tools, capacity of human resources, etc. that will be identify through the collaborative research process.
The first phase of the project consists of setting a baseline to assess the needs, challenges and current practices of including climate change in the evaluation of hydroelectric asset values. This will be undertaken through interviews with different stakeholders, workshops with project partners and a thorough literature review of best practices and methodological developments. Subsequent phases of the project include the development of the methodological framework, the preparation of case studies, as well as results dissemination through scientific articles, webinars and workshops.
Our presentation will discuss the project context and its objectives, as well as the insights derived from the concluded first phase of the project. Attendees will learn about scientific development and the best practices identified in the industry. They will also gain insight into the results from the workshops and the interviews. The presentation will enrich the reflection of the financial implications of climate change impacts, and will discuss tools and methods to include them in the evaluation of hydroelectric asset values.
NRC Frazil Ice Research Facility
Martin Richard, Andrew Cornett
Dr. Martin Richard, National Research Council, Canada Dr. Andrew Cornett, National Research Council, Canada (Presenter)
Frazil ice is a type of ice that forms in fast-flowing supercooled water, consisting of small ice crystals in suspension in the water column which are notorious for adhering to all submerged objects they come in contact with. Frazil is infamously known for blocking water intakes in rivers and estuaries, as crystals stick and build up on the intakes’ trash racks. Such blockages negatively impact water supply facilities, hydropower plants, nuclear power facilities, and vessels navigating in cold waters, and can lead to dramatic impacts, such as a town being left with insufficient water reserves for fire protection, a nuclear facility not getting the cold water required for cooling, or a vessel being forced to shut down its engines and drift.
Our theoretical knowledge of frazil ice is currently quite limited, in part because field and laboratory data on frazil ice is difficult to obtain and hence relatively scarce. New experimental research and field data is needed to gain a much improved understanding of frazil growth and its interaction with structures. Hopefully, such new understanding will eventually lead to theoretical and numerical models that can reliably predict frazil growth and its impacts. While several small-scale laboratory studies have been reported in the literature (in small tanks of ~1 m3, e.g. Clark and Doering, 2006), very few studies document the successfull generation of frazil ice on a larger scale (> ~2 m3, e.g. Ettema et al., 2003; Smedsrud, 2001).
This paper will describe the development and operation of a new frazil ice research facility at the National Research Council of Canada where frazil can be reliably generated and its interaction with objects studied under controlled repeatable conditions. The new facility features a water volume of 120 m3 and turbulent flow speeds up to 1 m/s. The use of this new facility to investigate the effects of frazil on the blades of a hydrokinetic turbine will also be described.
Clark, S. and J.C. Doering 2006. Laboratory Experiments on Frazil-Size Characteristics in a Counterrotating Flume. Journal of hydraulic engineering (ASCE), 132(1): 94-101.
Ettema, R., Chen, Z. and J. Doering, 2003. Making frazil ice in a large ice tank. Proceedings of the 12th CRIPE conference, Edmonton, AB, June 19-20, 2003.
Smedsrud, L.H., 2001. Frazil-ice entrainment of sediment: large-tank laboratory experiments. Journal of Glaciology, 47(158): 461-471.
Erosion and Scour
Effects of relative bed coarseness and blockage ratio on local scour around bridge abutments
PENG WU, Ram Balachandar
Dr. PENG WU, University of Regina (Presenter) Dr. Ram Balachandar, University of Windsor
Based on a series of hydraulic experiments conducted at the Sedimentation and Scour Study Laboratory at the University of Windsor, the effect of relative bed coarseness and blockage ratio on local scour around bridge abutments are presented. Scour around semi-circular bridge abutments with different diameters are compared under identical flow conditions for several blockage ratios. An analysis of blockage for different abutment is used to provide a clearer understanding on the impacts of relative bed coarseness and blockage ratio on local scour profile and maximum scour depth. Results of this study indicate that both equilibrium scour depth and scour profile are affected by blockage ratio. Clear differences can be noted in the scour geometry even for small changes in blockage ratio. With the increase of relative bed coarseness, the scour width and scour depth decrease correspondingly. Additionally, the approach flow depth shows a strong influence on the scour geometry. The study provides additional support for considering relative bed coarseness and blockage ratio in local scour prediction around bridge foundations.
Evaluation of channel blockage as a governing influence in local scour experiments
Priscilla Williams, Ram Balachandar, Tirupati Bolisetti, Vesselina Roussinova, Mia Marrocco
Ms. Priscilla Williams, University of Windsor (Presenter) Dr. Ram Balachandar, University of Windsor Dr. Tirupati Bolisetti, University of Windsor Dr. Vesselina Roussinova, University of Windsor Ms. Mia Marrocco, University of Windsor
Previous evaluation of dimensionless parameters used in governing pier scour depth prediction methods has indicated that channel blockage influences local scour geometry in laboratory experiments. The majority of prediction methods are functions of previously-defined scour-governing parameters (Williams et al. 2017), and do not include parameters related to so-called blockage effects. The effect of blockage ratio, defined as the ratio between pier diameter (D) and channel width (b), has been erroneously defined in literature as negligible when blockage ratio is less than 10 percent. Recent investigations have determined that changes in values of blockage ratio as minimal as 0.5 percent influence scour geometry (Hodi 2009, D’Alessandro 2013), even when blockage ratio is less than the stated threshold of 10 percent.
Sidewall influence on the flow characteristics around a bluff body can be reduced using Us, the magnitude of streamwise velocity along the separating streamline (Ramamurthy and Lee 1973). Using a similar procedure, the present study investigates the influence of blockage ratio on bridge pier scour. Scour experiments for cylindrical piers were carried out at low values of blockage ratio with all other scour-governing parameters held constant in order to isolate the effect of sidewall influence. Experimental work was conducted in a recirculating horizontal flume at the University of Windsor under model conditions. Results indicated that scour depth increases with increasing blockage ratio; furthermore, as scour progresses downstream of the scour hole, dune formations reach the sidewalls at a shorter distance downstream for a higher blockage ratio. Experimental results from the current investigation were analysed together with benchmark results from literature in order to develop a new scour depth prediction method based on Us. The present study also includes a discussion on influence of blockage ratio on scour geometry around triangular piers, through analysis of literature results.
References: 1. D’Alessandro, C. 2013. Effect of blockage on circular bridge pier local scour. M.A.Sc. thesis, Department of Civil and Environmental Engineering, University of Windsor, Windsor, Ont. 2. Hodi, B. 2009. Effect of blockage and densimetric Froude number on circular bridge pier scour. M.A.Sc. Thesis, Department of Civil and Environmental Engineering, Faculty of Engineering, University of Windsor, Windsor, Ont. 3. Ramamurthy, A.S., and Lee, P.M. 1973. Wall effects on flow past bluff bodies. Journal of Sound and Vibration, 31(4): 443–451. doi:10.1016/S0022-460X(73) 80259-7. 4. Williams, P., Bolisetti, T., and Balachandar, R. 2017. Evaluation of governing parameters on pier scour geometry. Canadian Journal of Civil Engineering, 44(1): 48–58. doi:10.1139/cjce-2016-0133.
Experimental study on the effect of dike geometry on the breach outflow and erosion rates during overtopping of non-cohesive homogeneous embankment
AMANJ RAHMAN, Ioan Nistor, Julio Angel Infante Sedano
Mr. AMANJ RAHMAN, university of Ottawa (Presenter) Dr. Ioan Nistor, University of Ottawa Dr. Julio Angel Infante Sedano, University of Ottawa
The paper will present the results of a comprehensive experimental program conducted to obtain the effect of downstream slope on the planar breaching progress and outflow hydrograph of homogenous non-cohesive embankments due to overtopping. Visualizing flow by injecting fluorescent dye and using LED UV Blacklight in a light controlled room combined with high-speed cameras provided high-accuracy data of high temporal and spatial resolution of the processes investigated. Downstream slopes of (1:2, 1:3 and 1:4) were tested with the initial overtopping head of 5 and 10 cm respectively. The time-history of the pore-water-pressure (PWP) during overtopping flow on the downstream face were recorded using micro-tensiometer-transducer probe assemblies (MTTPA), assembled and calibrated conducted in the Geotechnical and Hydraulic Engineering Laboratories at the University of Ottawa, Canada. Styrofoam balls (2-3) mm size painted with fluorescent paint were used as a seeding particle to measure surface velocity, in combinations with a high-speed Phantom 410L (HSPC) camera with a recording capacity of 1000 fps. The image processing and tracking particles velocity were achieved using Davis@ commercial software.
The authors overcame significant difficulties in measuring outflow hydrograph due to the shallowness of the flow and the highly unsteady state flow. Past researchers used different methods to estimate breach hydrographs such as v-notch weir installed at the downstream end of the experiment, or hydrologic routing of the reservoir or most common one is broad-crested weir formula. The element of novelty of this work is the deployment of recent technology and image processing tools made possible to use particle tracking velocimetry (PTV) in measuring overtopping flow hydrograph.
The hydrographs computed for the three embankment configurations indicated that erosion rate for steeper slope under the high initial overtopping head is quite faster due to the acceleration of flow and high shear stress applied on the bed material. In contrast, with the low initial overtopping head (5cm), the downstream slope has less impact on peak-flow rather than delaying the erosion progress.
A NEURAL NETWORK-BASED APPLICATION FOR AUTOMATED DEFECT DETECTION FOR SEWER PIPES
Xianfei Yin, Yuan Chen, Qin Zhang, Ahmed Bouferguene, Hamid Zaman, Mohamed Al-Hussein
Mr. Xianfei Yin (Presenter) Ms. Yuan Chen, University of Alberta Mrs. Qin Zhang Mr. Ahmed Bouferguene, University of Alberta, Campus Saint-Jean Mr. Hamid Zaman, University of Alberta Dr. Mohamed Al-Hussein, University of Alberta
Manual defect identification for sewer pipes based on closed-circuit television (CCTV) monitoring is time-consuming and error-prone. In order to address this issue, an innovative approach is to extract image frames from the video, examine whether the frames include defects, and classify these defects into different types (e.g., cracks or fractures). Specifically, a classifier based on a neural network is proposed in this paper, which consists of four parts: (1) extracting the color frames including defects from the video; (2) tailoring the frames in order to highlight the defect part; (2) transferring information in the tailored frames including defect shape and depth information into a matrix; (3) Using the matrix as inputs to generate a classifier by means of neural network; (4) Testing the built classifier. The proposed framework is then applied to a case study of Edmonton in order to automatically detect the number and location of defects on sewer pipes and conduct a condition assessment for each pipe.
Life-Cycle optimization for facility financial management of residential communities
Dina Saad, Hesham Osman
Ms. Dina Saad, Cairo University (Presenter) Dr. Hesham Osman, Cairo University
The residential real estate market in Egypt, especially the one for gated communities, has witnessed significant growth to meet the increasing demand for housing units. This demand has been driven by in-creasing population growth and relocation of residents to less crowded areas. Accordingly, many high-end residential communities, commonly known as compounds, have been developed in new suburbs in the outskirts of Cairo. In spite of the significant investment in this sector, the performance and the quality of the provided housing facilities in the majority of these compounds have rapidly deteriorated over time due to lack of maintenance. This is partly due to insufficiency of funds to cover the expenses associated with the facilities’ life cycle and misalignment between the financial resources and the costs incurred. This financial gap is due to missing pre-defined level of service (LOS) which subsequently lead to improper allocation of funds, high inflation rates, and incomprehensive study of the implications of the funding strategies on the facilities performance. Accordingly, this research paper presents a service-level based optimization model that determines the optimum level of service for each facility service to maximize the overall facilities’ performance under the limited funds available, considering the life cycle costs over a predefined time horizon. Moreover, the model allows conducting sensitivity analysis to examine the facilities’ performance under different funding strategies, and to determine the timing to introduce supporting financial resources. Using a real case study of a high-end residential compound, the proposed optimization model proved to be able to arrive at an optimum solution that determines the optimum combination of LOSs for each service without com-promising the overall performance of the residential community under the limited funds available. This model, therefore, is a potential tool that can help provide quality facility management in a cost-effective manner.
PROCUREMENT OF FACILITY MAINTENANCE
Laird Ferguson, Lloyd Waugh
Mr. Laird Ferguson, MacLean Construction (Presenter) Dr. Lloyd Waugh, University of New Brunswick
This paper provides a brief review of the literature, provides a preliminary review of Defence Construction Canada’s (DCC) request for proposals (RFP) template, and provides a preliminary review of a specific Public Works and Government Services Canada’s (PWGSC) RFP. The scope of the DCC RFP template is limited to maintenance and support services for a selection of buildings within a geographical area for a defined period, e.g., five years. The three service categories included are hard services (exterior and interior maintenance, electrical, etc), soft services (road and grounds, housekeeping, etc), and ancillary services (monitoring, budget control, etc). The scope of the PWGSC RFP includes management services, services to establish third-party leases and agreements; lease administration services, project delivery services, and various optional services. The differences between the scopes, submission requirements, and evaluation processes are reviewed. The title of the RFPs provide an indication of the difference in the scopes, the DCC RFP is titled “Facility Maintenance Support Services” and the PWGSC RFP is titled “Real Property - 1 Property Management and Project Delivery Services.” The submission requirements and evaluation of the proposal also differ. The DCC RFP requires technical and financial responses that are evaluated on a scale of 0 to 3. The PWGSC submission requirement is comprehensive and detailed, with several rubrics provided to assist bidders in preparation, as well as to understand the evaluation process. This paper provides a preliminary review for those interested in facility management and identifies areas for future research.
Wi-Fi Router Network-based Occupancy Estimation to Optimize HVAC Energy Consumption
Krishna Chaitanya Jagadeesh Simma, Susan M. Bogus, Andrea Mammoli
Mr. Krishna Chaitanya Jagadeesh Simma, University of New Mexico (Presenter) Dr. Susan M. Bogus, University of New Mexico Dr. Andrea Mammoli, University of New Mexico
More than half of commercial building stock in the United States were built before 1980 with a median age of 32 years in 2012. In the age of Smart and Green buildings, owners tend to incorporate expensive sensor infrastructure to reduce building energy consumption and improve the building occupants’ satisfaction, efficiency, and comfort levels. In this context, studies explored the influence of building occupancy on its energy consumption. Recently, researchers shifted their focus towards exploring different occupancy estimation techniques with both dedicated sensors and existing infrastructure (e.g. CO2 sensors, Smart meters, temperature and humidity sensors, and wi-fi networks). However, there are concerns about the cost effectiveness, computational effort, accuracy and privacy protection for existing techniques. This study explores the usage of number of IP addresses connected to a wi-fi router to estimate the occupancy within a building. To this end, occupancy patterns in a thirty-year-old university building are estimated using existing wi-fi infrastructure and compared and calibrated to ground data obtained manually and from dedicated occupancy estimating sensors to evaluate the accuracy. The estimated occupancy data patterns using existing wi-fi network represent a cost-effective method of occupancy estimation with less computational processing and reduced privacy concerns, that could assist owners in the decision-making process towards investing into smart and energy efficient technologies.
Fiber Reinforced Concrete
Experimental study on flexural performance of FRC beam specimens for bridge barrier applications
Morteza Fadaee, Khaled Sennah
Mr. Morteza Fadaee, Ryerson University (Presenter) Dr. Khaled Sennah, Ryerson University
Fiber-Reinforced Concrete (FRC) are recently used in structural elements in order to provide with a more cost-effective design. Although specific details have not yet been provided for FRC bridge barriers in the Canadian Highway Bridge Design Code (CHBDC), a residual strength index with respect of the post-cracking flexural properties of FRC beam specimens is indicated in CHBDC as an initial step for designing FRC bridge barriers. In this study, two flexural-performance standard tests, namely: ASTM C1399 and ASTM C1609, were carried out as mentioned in CHBDC on FRC beam specimens. The tests provide with the corresponding results for evaluation of the residual strength index required by CHBDC for FRC-reinforced structures. The two tests were conducted on a total of 30 specimens with a size of 200x200x700 mm including three different fiber rates, namely: 0.5%, 1.0% and 1.5%. The results include the average residual strength and modulus of rupture for all specimens for comparison and concluding with an efficient fiber rate for bridge barrier applications.
Mechanical Performance and Plastic Shrinkage Characteristics of Concretes Reinforced with Basalt Fibers
John Branston, Emad Booya, Karla Gorospe, Sreekanta Das
Mr. John Branston, University of Windsor Dr. Emad Booya, University of Windsor (Presenter) Ms. Karla Gorospe, University of Windsor Dr. Sreekanta Das, University of Windsor
Unreinforced concrete (plain concrete) is a brittle material that has low tensile strength. Therefore, plain concrete can easily crack when subjected to tensile stress. To reduce these cracks, randomly distributed fibers are usually added to concrete. These fibers usually tries to bridge and arrest the cracks and thus, improve the mechanical behavior. On the other hand, the early-age cracking that result from plastic shrinkage is considered as a major problem in concrete applications. Therefore, to mitigate the shrinkage cracking, short, randomly distributed fibers are added to the plain concrete. The reduction in plastic shrinkage is because the fibers will reduce the overall shrinkage strains and decreases the possibility of tensile stresses exceeding the tensile strength of the concrete.
The use of sustainable fibers in reinforcing concrete composites increased dramatically in recent years. One of these fibers is chopped basalt fiber that gained popularity in concrete applications due to its excellent mechanical properties and environmentally friendly manufacturing process. The fibers typically have a tensile strength slightly higher than E-glass fibers, and many times greater than steel fibers. In addition to plain chopped basalt fibers (BF), a new basalt concrete reinforcement product called minibars (MB) has recently been developed. The minibars are essentially a scaled down version of basalt fiber reinforced polymer rebar.
Â This study consisted of two phases. In phase I, The purpose of the experimental work presented in is to compare the pre- and post-cracking mechanical behavior of concrete reinforced with plain chopped basalt fibres (BF), basalt minibars (MB), and commonly used hooked end steel fibers (SF). Filament fibers were not used in phase I tests as these fibers are typically used for crack control. The performance of the fibers were evaluated by flexural and drop-weight impact testing. However, in phase II, three different basalt fibers were used to reinforce concrete and mortar overlays for plastic shrinkage testing. Further, the objective was to evaluate the performance of these fibers in reducing the plastic shrinkage strain of unrestrained specimens, and to measure cracking severity of restrained specimens. The literature review showed that there is a gap in the research regarding the usefulness of basalt fibers in controlling the early-age crack.
Results from this study showed that the addition MB improved the first-crack strength of concrete subjected to flexural loading and impact loading. Furthermore, the different type basalt fiber were effective in mitigating the shrinkage strains and eliminating the shrinkage cracking.
Permeability Characteristics of Cementitious Materials Reinforced with Kraft Pulp Fibres
Emad Booya, Karla Gorospe, Adeyemi Adesina, Sreekanta Das
Dr. Emad Booya, University of Windsor (Presenter) Ms. Karla Gorospe, University of Windsor Mr. Adeyemi Adesina, University of Windsor Dr. Sreekanta Das, University of Windsor
The research on the application of environmentally friendly materials in construction has been increasing. Special attention has been given on the use of fibers originating from renewable vegetable sources such as cellulose pulp fiber. These fibers are green alternatives to conventional synthetic and other petrochemical based fibers. Cellulose fibers are promising reinforcing materials because of their availability, renewability, recyclability, and nonhazardous nature.
One of the well-known problems of concrete is degradation caused by the penetration of deleterious substances into the concretes by transport and diffusion. The inclusion of cellulose fiber is expected to potentially mitigate damages such as corrosion and spalling in cementitious materials by enhancing the microstructural permeable pores caused by the ingress of water and chlorides. Hence, this study was completed to determine the strength and permeability properties of cementitious materials reinforced with engineered Kraft pulp fibers. These fibers are called mechanically modified fiber (MMF) and chemically treated fibers (CTF). The performance of reinforced mixtures made of these two fibers were compared with a mixture made of traditional and commercially available unmodified (UF) pulp fiber. The MMF and CTF are proprietary to Domtar Inc. and to the best of the authorsâ€™ knowledge, they have not been used in any previous studies in fiber reinforced cement composites applications. The strength, and durability of fiber-reinforced concretes were assessed for compressive strength, chloride permeability, immersion absorption, and rate of absorption. Test results showed an increase in the permeability characteristics for the reinforced concretes. Hence, these fibres reduced the compressive strength and durability of reinforced concretes as compare to the unreinforced concrete. However, the two engineered fibres performed better than the unmodified fibre in terms of compressive strength, chloride ion permeability and water sorptivity. The study concludes that these two engineered pulp fibers are better alternatives to commercially available unmodified cellulose fibers.
Predicting The Shear Resistance of SFRC Beams
This paper presents a literature review on the shear behaviour of steel fiber reinforced concrete (SFRC) and proposes equations for predicting the shear resistance of SFRC beams. First a large database of test results is used to evaluate the effect of various parameters on the shear response of SFRC beams. In addition, the paper reviews various equations proposed in the literature to predict the shear capacity of SFRC beams. The paper then presents equations which can be used to predict the shear resistance of SFRC beams. The shear resistance equations modify the general method of the 2004 CSA A23.3 Standard to account for the effect of steel fibers on shear capacity. The method proposed in this paper and equations proposed in the literature are used to predict a large database of SFRC beam test results. The results show that the method presented in the paper provides reasonably accurate predictions of shear capacity for beams having a wide range of properties.
Green and sustainable design and construction (1)
A BUILDING ENERGY AND HEALTH CONDITIONS MONITORING STRATEGY FOR CANADIAN BUILDING SECTOR
Tharindu Prabatha Hewa Godella Waththage, Hirushie Karunathilake, Rajeev Ruparathna, Rehan Sadiq, Kasun Hewage
Mr. Tharindu Prabatha Hewa Godella Waththage, University of British Columbia (Presenter) Dr. Hirushie Karunathilake, University of British Columbia, Canada Dr. Rajeev Ruparathna, University of Windsor Dr. Rehan Sadiq, University of British Columbia, Canada Dr. Kasun Hewage, University of British Columbia, Canada
Energy-related decision making for a building is a demanding task, due to the challenges associated with energy system performance prediction. Performance prediction can be done either with simulation tools or by referring to the building energy performance databases. However, in Canada, interactive building energy performance databases that allow the evaluation of different energy efficiency improvement options based on actual data are not found. Therefore, most of the Canadian building construction and retrofitting projects adopt the energy simulations. However, simulation results can contain errors due to multiple reasons including data uncertainty and challenges in capturing system deterioration. Therefore, actual energy performance data is needed to support the simulation results and to inform the designers regarding the actual performance of different energy system configurations under varying environmental conditions over the years. Thus, post-occupancy energy monitoring mechanisms and building energy performance databases need to be developed for continuous data acquisition. Building energy performance is known to have a high correlation with the building indoor environmental quality, which creates high health impacts on occupants. Therefore, human health impacts associated with building energy efficiency measures have to be considered at the design stage. However, lack of information about the actual indoor environmental quality impacts associated with different retrofits and operational strategies poses challenges to building designers. Occupant health and energy use monitoring needs to be mandated for new buildings in Canada, in order to overcome these challenges. Moreover, comprehensive databases containing both energy and health performance of buildings need to be developed to inform the building designers and construction industry as a whole. This study discusses the requirements for developing a health-energy monitoring mechanism for Canada. The key parameters need to be monitored and the challenges are identified.
Costs of Green Residences in Canada: An Economic and Environmental Analysis of Developing Renewable Powered Building Clusters
Hirushie Karunathilake, Tharindu Prabatha Hewa Godella Waththage, Kasun Hewage, Rehan Sadiq
Dr. Hirushie Karunathilake, University of British Columbia, Canada (Presenter) Mr. Tharindu Prabatha Hewa Godella Waththage, University of British Columbia Dr. Kasun Hewage, University of British Columbia, Canada Dr. Rehan Sadiq, University of British Columbia, Canada
The interest in renewable energy as an alternative to conventional fossil fuels has grown in recently, in response to the environmental and economic concerns of energy use. Energy Step Codes are now mandating net-zero energy buildings, to facilitate the emissions reduction targets of Canada at provincial and federal levels. While net-zero energy buildings can deliver emissions benefits, the additional costs of implementing energy efficiency measures and on-site renewable generation is a major problem to the construction industry and community developers. While studies indicate that buyers are willing to pay a premium for “green” buildings, it is difficult to establish the economic viability of net-zero buildings without conducting a comprehensive economic assessment. This research proposes to quantify the economic and environmental impacts of on-site RE integration for residential building clusters. Building level-and cluster centralised RE facilities will be considered in the assessment, and the incremental costs of converting building clusters to net-zero status will be investigated. Based on the assessment, the increase in housing prices for different housing types (i.e. single-family detached, single-family attached, multi-unit residential buildings) due to net-zero or near-zero conversion will be identified using a scenario-based approach. Moreover, the residential emissions benefits that can be achieved by different RE investments will be quantified using life cycle assessment. Based on the economic and environmental impact analysis, the effect of clean energy transformation of housing affordability will be discussed. The findings will be useful to the construction industry in making their investment decisions for net-zero ready construction.
Integrated Building Design and Energy Simulation
Coleen Dorey, Mojtaba Valinejadshoubi, Ashutosh Bagchi
Ms. Coleen Dorey Mr. Mojtaba Valinejadshoubi, Concordia University Dr. Ashutosh Bagchi, Concordia University, Canada (Presenter)
Energy consumption in buildings constitute a significant portion of the total energy demand in Canada (about 40%). While the design and construction of energy efficient buildings is gaining momentum, it is important to have an integrated process for the design. The present article focuses on the integrated design process, especially at the conceptual phase to account for energy efficiency and adoption of renewable energy in buildings. The research is divided into three sections or phases. Phase one includes the optimization of the design of a single-family home in Montreal based on the following criteria; space, aesthetics, energy performance and cost. Each of the above criteria was evaluated over 22 designs and the importance of each category weighted according to public opinion. As a result, cost was considered as the most important category (weighting of 30%), followed by space (28%), energy performance (25%) and aesthetics (17%). The top three designs totaling the highest cumulative scores are further evaluated in phase two. Phase two, includes a detailed analysis of the building envelope, incorporating current market materials and following the insulating requirements of the Quebec Construction Code (Amended from the National Building Code of Canada 2010). Using Autodesk Revit, an energy analysis was conducted, and the top performing building was selected for further analysis and improvements. Characteristics of the top performing building include, simple building geometry, a brick façade, majority of the windows located on the North and South façade, and a hip roof over the living area with a flat roof over the garage. The energy analysis results are carried over to phase three, where the possibility of renewable and sustainable energy saving techniques are explored to reduce the external energy required to meet the demand of the building.
Optimizing selection of building materials and fixtures to reduce operational costs
SAMUEL Hutchison, Mahdi Ghafoori, Moatassem Abdallah, Caroline Clevenger
Mr. SAMUEL Hutchison, University of Colorado Denver Mr. Mahdi Ghafoori Dr. Moatassem Abdallah, University of Colorado, Denver, USA (Presenter) Dr. Caroline Clevenger, University of Colorado, USA
Buildings generate a considerable amount of greenhouse gases throughout their lifecycle. 80% of energy is typically consumed during the operating phase of the building lifecycle, while the construction and demolishing phases generate only 20%. Furthermore, building typically undergo a number of renovations stages during their life. This can include modifications to fixtures and equipment such as lighting fixtures and HVAC equipment; or building envelope such as windows, glazing, and wall and roof insulation. This paper presents the development of an optimization model that is capable of identifying the optimal selection of building upgrades to minimize building operational cost within a specified upgrade budget. The optimization model is expected to support building owners and their representatives in their ongoing efforts to minimize the operational cost of their buildings where renovation is planned. The optimization model is developed in four main steps. These steps include (1) Identifying decision variables that represent the desired building upgrade measures; (2) formulating objective function to minimize operational cost of existing buildings; (3) modeling all relevant constraints to ensure the practicality of the model results; and (4) implementing the model computations using Genetic Algorithms. The capabilities of the model are demonstrated using a case study of a commercial building. The results of the model showed a 42% reduction in operational costs with an upgrade budget of $125,000. Most of the operational cost savings were attributed to the installation of the photovoltaic system which saved about $2,262 in operating costs annually. The model was run with two other upgrade budgets of $75,000 and $175,000 to show the impacts of the upgrade budget on annual operating costs.
Optimizing Selection of Existing Building Upgrades to Maximize their Sustainability
Moatassem Abdallah, Khaled El-Rayes
Dr. Moatassem Abdallah, University of Colorado, Denver, USA (Presenter) Dr. Khaled El-Rayes, University of Illinois at Urbana-Champaign
Existing buildings are often in urgent need for upgrading to improve their performance in terms of energy and water consumption, as well as carbon emissions. Building owners and operators often allocate budgets to upgrade their buildings and they always seek identification of building upgrades to improve performance of their buildings and achieve green certification. This paper presents the development of an optimization model that is capable of identifying building upgrades to achieve green certification for existing buildings. While several green certification programs are currently available for existing buildings, this paper focuses on Leadership in Energy and Environmental Design (LEED) rating system for existing buildings. The optimization model is developed in three main steps, including model formulation step that focuses on model decision variables, objective function, and constraints; computational step that focuses on selecting optimization algorithm and implementing the model calculations; and evaluation step that focuses on testing and refining the model performance. A case study of an existing building is used to demonstrate the model capabilities. The optimization model was able to identify the optimal selection of buildings upgrades to achieve LEED certification for existing buildings with minimum upgrade budget or maximize the sustainability of the building within a specified budget. The optimization model is expected to support decision makers, building owners, and operators to identify optimal selection of upgrades to improve performance of existing buildings and achieve sustainability certification programs.
SOLAR PHOTOVOLTAIC ELECTRICITY FOR SINGLE-FAMILY DETACHED HOUSEHOLDS: LIFE CYCLE THINKING-BASED ASSESSMENT
Piyaruwan Kaluthantirige, Anber Rana, Kasun Hewage, Shahria Alam, Rehan Sadiq
Mr. Piyaruwan Kaluthantirige, University of British Columbia (Okanagan Campus) (Presenter) Ms. Anber Rana Dr. Kasun Hewage, University of British Columbia, Canada Dr. Shahria Alam, University of British Columbia Dr. Rehan Sadiq, University of British Columbia, Canada
Electricity generation using solar photovoltaic (PV) can be considered as one of the key low-emission energy technologies that reduce building net operational level emissions compared to the fossil fuels-based energies. Small-scale grid-tie solar (PV) systems are being widely used in many parts of the world. These systems would be benefitted to the investors by reducing household level operational GHG emissions and securing low energy prices for long-term. Solar (PV)â€“based electricity generation in Canada can be improved immensely to achieve local emission targets while securing healthier energy rates for the consumers. However, there is a lack of knowledge on life cycle impacts of solar (PV)-based electricity generation in single-family detached households in Canadian regions with low-emission grid electricity. The objective of this study is to conduct an investigation to obtain the feasibility of small-scale solar (PV) systems for households in South British Columbia mountain climate region, Canada using life cycle thinking approach. The effect of domestic activities and transportation was used to identify the net energy use of the household throughout its entire life. The life cycle impact assessment and the life cycle cost assessment results were used to compare the impacts of different household alternatives. The results of this study showed that households with solar (PV) systems and electric transportation facilities indicated comparatively lower environmental impacts and higher long-term financial benefits. However, the upfront costs of households with solar systems are relatively high which may have adverse effects on the purchasing decisions. The short-term use of solar (PV) systems may result in higher cost and environmental impacts.
Green and sustainable design and construction (2)
Application of Fuzzy AHP to Minimize Concrete Waste
Ahmad Mdallal, Ahmed Hammad
Mr. Ahmad Mdallal, University of Sharjah Dr. Ahmed Hammad, University of Alberta (Presenter)
Achieving sustainability is a major global challenge pressing on construction industry to reduce the pollution caused by its activities. Achieving sustainability requires changing the traditional cost/benefit analysis, which focuses only on financial gains, to a multicriteria decision-making model taking into consideration the three pillars of sustainability: economical, environmental and social aspects.
Construction waste is considered to be one of the main barriers towards achieving sustainability in construction. As per previous studies, concrete waste is the number one contributor to construction waste. This study is proposing a generic model to enable decision makers to select the most sustainable alternative to reduce concrete waste on construction sites.
The study starts with a comprehensive literature review regarding construction waste, Multi Criteria Decision Making (MCDM) techniques and their application to solve the construction waste problem. After that, Fuzzy Analytic Hierarchy Process (FAHP) technique is selected to minimize concrete waste. The developed model defined selection criteria and compared applicable alternatives to reduce concrete waste on construction sites with respect to the three aspects of sustainability: economical, environmental, and social using pairwise comparison matrices. Technical criteria has been also considered in the decision-making model. A case study has been conducted and several meetings have been held with various experts from the construction industry in United Arab Emirates. During these meetings, the experts defined selection criteria and agreed-upon weights to be assigned to the proposed criteria and applicable alternatives. Finally, the proposed model has been validated using the consistency test to eliminate inconsistency in the judgments of each pairwise comparison matrices as well as for the whole hierarchy. Results show that Concrete Prefabrication is the most sustainable alternative to solve this problem according to experts’ judgment.
The developed model defines the most important decision making criteria required to minimize concrete waste and introduces a new generic application to FAHP. The model can be implemented on any construction site and can be utilized by any group of expert decision-makers. Produced model results reflects experts’ preferences, increases awareness of sustainability measures and introduces a multicriteria consistent technique into the decision-making process.
Keywords: Construction Waste, Fuzzy Analytical Hierarchy Process, Multicriteria Decision-Making, Construction Waste Reduction.
Comparative Analysis of Energy Consumption Using DOE-2 Building Energy Analysis Program: A Case Study
Behzad Rouhanizadeh, Sharareh Kermanshachi
Mr. Behzad Rouhanizadeh, University of Texas at Arlington Dr. Sharareh Kermanshachi, University of Texas at Arlington (Presenter)
The energy use has been growing so fast within last decades due to the rapid developments and increase in population. Several social, economic and environmental reasons raised concerns to lessen the energy use globally. In developed communities, energy consumption in buildings of various usages has a large contribution of the overall energy use. Therefore, efficient energy use in the buildings can help to optimize the energy consumption significantly. In this study, the energy performance and the associated operating costs of a building have been calculated and compared with experimental amounts. For this purpose, DOE-2 computer simulation program was implemented. DOE-2 program is capable of detailed and quick energy consumption analysis of buildings. The energy used to produce heat consumed most of the energy comparing the other users of energy in the building. The results of this study revealed that the consumed heat in the case study building was more than the experimental amounts, while the consumed electricity was very close to the experimental amounts. The findings of this study helps to identify the issues with DOE-2 energy software as well as providing empirical evidence to validate the program, and gives insight to the designers for designing less energy consuming buildings or energy-aware design.
Energy Code-Compliant Housing Design: A Cost and Energy Perspective
Regina Dias Ferreira, YuXiang Chen, Haitao Yu, Mohamed Al-Hussein
Ms. Regina Dias Ferreira, University of Alberta (Presenter) Dr. YuXiang Chen Mr. Haitao Yu, Landmark Building solutions Inc. Dr. Mohamed Al-Hussein, University of Alberta
The residential sector is the third highest end-user of energy in Canada, accounting for ~17% of all energy consumed in the country. Moreover, housing in Canada consumes approximately 214 kWh/m2 per year, and ~63% of this consumption results from space heating. Thus, in an effort to improve the energy efficiency of housing, the provincial government in Alberta, Canada, recently updated its building code, including a section dedicated entirely to energy-efficiency requirements applied to new housing and small buildings in the province. Housing built compliant to this improved energy standard will have better energy performance. On the other hand, code-compliance is also expected to lead to an increase in initial housing construction cost due to changes in construction practice. In this context, this paper investigates the impacts of code-compliance on housing construction practice and operation costs for housing in Edmonton, Alberta. Selection of least-construction-cost upgrades for building envelope (attic ceiling, above- and below-grade walls, and windows) that meet code-specified thermal insulation values is discussed. Then, a 30-year lifecycle analysis is conducted using HOT2000 simulation to estimate the energy performance and operation cost of a home built using current construction practices and using the proposed least-construction-cost upgrades. The results obtained indicate that a reduction of ~12% on energy consumption is achieved by deploying the upgrades proposed by this study.Â
SUSTAINABLE DESIGN OF REINFORCED CONCRETE FLAT-PLATE BUILDINGS BASED ON COST, EMBODIED ENERGY, AND CARBON FOOTPRINT
Ahmed Noman, Ashutosh Bagchi, Andreas Athienitis
Mr. Ahmed Noman, Concordia University (Presenter) Dr. Ashutosh Bagchi, Concordia University, Canada Dr. Andreas Athienitis
Energy is required in all phases of a building life cycle. Embodied energy and carbon emissions of a building are associated with the production, transportation, disposal, and recycling of materials, and during their construction and demolition. A cost-optimized structural design of individual members is obtained by selecting the quantities of materials that satisfy a certain design-code at a minimum cost. For a reinforced concrete structural element, concrete and rebars are optimized for cost. A member thus proportioned for a minimum cost may not always result in lower embodied energy and carbon emission. A different design approach is needed to reduce the embodied energy and carbon to a lower level. In this study, the objective functions for cost, embodied energy, and CO2emission were defined and used in the structural design of a set of RC flat-plate residential buildings with 5-, 10-, and 15-storeys, located in Montreal, Canada. The trade-off between the cost and two other variables was studied. It has been found that some significant reduction in embodied energy and CO2emission is possible for a small increase of the cost for the 5-, 10-, and 15-storey variants. For an optimized solution, the maximum reinforcement ratio of columns has been found to increase with the building height. A slab thickness taken 24% smaller than the minimum thickness specified by CSA 23.3-14 has been found to be most effective in meeting the objective of cost optimization and embodied energy and CO2emission reduction.
Health and safety (1)
BENCHMARKING CONSTRUCTION SAFETY PERFORMANCE AT A GLOBAL LEVEL: A CASE STUDY OF US, CANADA, AND NEW ZEALAND
Yuting Chen, Arash Shahi, Brenda McCabe, Awad Hanna, Mahdi Safa, Majeed Safa, Douglas Hyatt
Ms. Yuting Chen, University of Toronto Dr. Arash Shahi, University of Toronto (Presenter) Dr. Brenda McCabe, University of Toronto Dr. Awad Hanna, University of Wisconsin-Madison Dr. Mahdi Safa, Sam Houston State University Dr. Majeed Safa, Lincoln University Dr. Douglas Hyatt
Construction safety plateau has become a global issue. To sustain the continuous improvement of the global construction safety performance, research studies on construction safety performance at a global scale, i.e. comparing safety performance across countries, are needed. To fill in this gap, this paper starts with a preliminary study by comparing the safety performance of the Canada, US, and New Zealand construction sites and by investigating the impact of three demographic factors on construction safety performance of workers, including age, work experience, and union membership. Safety surveys were collected from 2015 to 2017. In total, 837 surveys were collected from Canadian construction sites, 420 surveys were from US construction sites, and 40 were from New Zealand. The major findings are as follows. First, the top five physical injures that were reported most frequently are the same across the 3 countries, including cut, puncture, or open wound, headache or dizziness, strain or sprain, persistent fatigue, and skin rash or burn. Second, the top five unsafe events that were reported most frequently are the same across the 3 countries, including overexerted, slipped, tripped, or fell on the same level, pinch, exposed to chemicals, and struck against something fixed. Third, the most frequently reported unsafe event for all the 3 countries is overexerted. Finally, union membership has an extensive impact on the occurrence of safety incidents for both Canada and US sample. In future, more data are needed from New Zealand construction sites to enable further exploration.Â
Characteristics of the Emission of Particulate Matters in Construction Site: A Comparative Study on a Timber and a Steel Construction Project
Shafayet Ahmed, Ingrid Arocho
Mr. Shafayet Ahmed, Oregon State University (Presenter) Ms. Ingrid Arocho, Oregon State University
Construction activities can produce significant amounts of air pollution having a direct effect on the surrounding environment. The level of emissions is distinct for each construction site based on the materials used for construction. Particulate matter (PM) is one of the most important pollutants produced during construction activities and is responsible for increasing human illness and mortality rate. This study aims to detect the concentration of PM emitted from two construction sites using different primary construction materials: cross-laminated timber (CLT) and steel. PM emissions were measured on both sites over a period of 5 days for four separate PM sizes (PM1.0, PM2.5, PM4.0, PM10) for a total of 600 data points. Data analysis performed for this study suggested that the steel building construction site had a higher concentration of PM than the CLT building construction site. Average concentration rate of the steel building construction site found to be 55-78% higher than the CLT project. The mean concentration of PM10 and PM4.0 was detected highest of all the sizes for both CLT and steel construction site. Both construction sites satisfied the United States Environmental Protection Agency (USEPA) standards for daily PM2.5 and PM10 concentration level. However, the mean concentration of PM2.5 (18.63 µg/m3) measured at the steel building construction site was found higher than the USEPA national average concentration rate (10.78 µg/m3). PM10 concentration level was found lower than the national average rate for both construction sites. Outcomes of the study provide a clear understanding of the characteristics of PM emitted from the construction sites. Comparative analysis shows that steel building construction sites are accountable for the production of higher concentration of particulate matters compared to the CLT building construction site. This study determines the concentration level of PM1.0 and PM4.0 which was mostly disregarded in previous studies on PM. The inclusion of PM1.0 and PM4.0 will be helpful to analyze the characteristics of different PM sizes.
Evaluating the Effects of Mental Workload and Spatial Cognition on Prevention through Design Activities
Construction Hazard Prevention through Design (CHPtD) is an injury prevention method that is achieved by reviewing design information to identify and mitigate hazards before they are encountered in construction. It has been postulated in construction safety literature that three-dimensional computerized design information is superior to two-dimensional paper-based design as 3D visualizations will allow users to spatially orient themselves within the design yielding increased hazard anticipation as compared to 2D designs alone. Unfortunately, it is unknown spatial cognitive ability affects hazard anticipation skills in design. To test this, a series of experimental trials were conducted with a mixture of 81 construction designers, construction supervisors, and civil engineering students to determine if spatial cognitive capabilities associated with various formats of design information influence hazard anticipation performance during CHPtD tasks. Participants were provided mutually-exclusive arrangements of traditional two-dimensional construction drawings, three-dimensional computer visualizations, and a combination of the two and asked to identify all possible safety hazards associated with three discrete construction work activities. Prior to the task, participants completed card and cube rotation tests to assess pre-existing personal spatial cognitive capability. Pearsonâ€™s correlation tests were used to measure the association among these variables. The results indicate that there is no association between spatial cognitive ability and hazard anticipation performance for the formats provided. The results conflict with the prevailing belief that 3D visualizations are superior to 2D visualizations in terms of promoting hazard anticipation.
Leading indicators for safety management: understanding the impact of project performance data on safety performance
Emad Mohamed, parinaz jafari, Shih-Chung Kang, Estacio Pereira, Simaan AbouRizk
Mr. Emad Mohamed, University of Alberta (Presenter) Mrs. parinaz jafari, University of Alberta Dr. Shih-Chung Kang, University of Alberta Mr. Estacio Pereira, University of Alberta Dr. Simaan AbouRizk, University of Alberta
The construction industry continues to experience an elevated number of accidents and fatalities, rendering safety a major concern for many construction companies. To develop more effective, proactive strategies capable of reducing future accidents, safety performance must be monitored and assessed prior to incident occurrence. Safety leading indicators can be used to proactively assess safety performance, provide insights into the effectiveness of an organizationâ€™s safety practices, and offer guidance on how to improve. Although useful, an agreed-upon set of leading indicators for proactively assessing safety performance has yet to be established in the literature. This research aims to investigate and test the feasibility of using project-related data together with safety-related data to more accurately assess proactive safety performance in industrial construction projects. Data utilized in this study were obtained from a large contractor in North America, pulled from eight industrial construction projects over a period of two years. Databases from different departments are matched and integrated into a single dataset. Correlation and feature selection techniques were used to identify the variables with the greatest impact on safety performance. Results of this study indicate that project performance data were associated with safety performance, demonstrating that project data, in addition to traditional safety leading indicators, can be used to build a safety management system to more effectively monitor safety in a project. Additionally, this study has shed light on the project performance metrics that could be collected by safety leaders to better predict safety performance on construction sites.
MINDFULNESS-BASED STRESS REDUCTION: AN INNOVATIVE WORKSHOP TO REDUCE STRESS AND IMPROVE THE PERFORMANCE OF CONSTRUCTION PROFESSIONALS
Mei-yung LEUNG, Khursheed AHMED
Dr. Mei-yung LEUNG, City University of Hong Kong Mr. Khursheed AHMED, City University of Hong Kong (Presenter)
The construction industry is known to be a stressful working environment, and construction professionals (CPs) face a great deal of stress at work that may harm their performance and health. In recent years, the popularity of mindfulness for managing stress has grown. Mindfulness-based stress reduction (MBSR) workshops are considered an effective and innovative approach to managing stress and improving performance. However, this new approach has not yet been explored in the construction industry. This study aims to investigate the impact of MBSR workshops on CPs, by comparing the mean differences in pre- and post-workshop and mean scores between MBSR group and a control group. A questionnaire survey was administered to both groups before and after the MBSR workshop. Semi-structured interviews were also conducted individually after the completion of the workshop. An independent t-test and Pearson correlation were used to examine differences in mindfulness characteristics, emotional stress, and organizational performance. The findings revealed that most of the mindfulness characteristic items received significantly higher scores among the MBSR participants as compare to non-participants. This result shows that mindfulness characteristics have a direct influence on CPs, improving their organizational performance by reducing their emotional stress. Pearson correlation showed a significant negative relationship between mindfulness characteristics and emotional stress and a positive association between mindfulness characteristics and organizational performance for MBSR participants. Therefore, this study reveals that MBSR workshops have a practical impact, both reducing stress and improving performance. It is thus recommended to introduce this new approach in organizations, particularly in the construction industry. Finally, we also propose new directions for further research, including longitudinal studies to identify the long-term effects of MBSR training in the construction industry.
Keywords: Construction Professional; Emotional Stress; Mindfulness Characteristics; Organizational Performance.
What Do People Like and Dislike About Construction Work? Views to Consider When Designing and Implementing Technology
Katherine Welfare, Matthew Hallowell, Fred Sherratt
Mrs. Katherine Welfare, University of Colorado at Boulder (Presenter) Dr. Matthew Hallowell, University of Colorado Dr. Fred Sherratt, Anglia Ruskin University
Development and integration of technology into construction is a robust field of study. Much of this research is focused on the feasibility of technology and its impact on improving project performance via enhanced safety, productivity, and quality. As technologies are considered, it is important to understand the preferences of construction workers and to ensure that positive attributes for the job are preserved and negative attributes of the work are avoided or mitigated. To better understand the preferences of construction workers, 108 interviews were conducted with workers on active commercial construction sites in Colorado. Workers were asked basic open-ended questions about their jobs and their perceptions of integrating emerging technologies into their work including questions such as why they chose the construction industry, what they enjoy and dislike about their jobs, and how they think technology could benefit them. Questions were purposely general and open to enable the use of discourse analysis and social constructivism, which allowed the researchers to preserve the richness of the discussion by documenting how different constructs were discussed. The results indicate that workers most enjoy task variety, seeing tangible and immediate results, social interaction, movement and exercise, autonomy, problem solving, and working with their hands. Conversely, the attributes most discussed in a negative way were health and safety issues, feeling rushed, paperwork, and repetition.
Additionally, workers felt that added technology would affect work pace, accuracy, productivity and efficiency and some noted that there was a concern that technology could be a distraction or possible safety hazard in the construction environment. Interestingly, the analysis revealed generational differences in the perceptions of technology. For example, the older generation prefers paper drawings while the younger generation favors using electronic drawings. The aging workforce shows a resistance to change while the younger generation is more receptive to change. The results from this research can be used when designing and implementing technology in construction. Researchers and practitioners can ensure that the positive attributes of work are enhanced and negative attributes are diminished. Further, it is helpful to understand worker perceptions before introducing technology to allow for strategic communication and roll-out that increases the likelihood and enthusiasm of adoption. Future research is needed to increase external validity through better geographic and cultural representation.
Health and safety (2)
Analyzing Hazardous Interactions on Construction Jobsites Using Social Network Analysis
Kasim Alomari, John Gambatese, Ahmed Albayati
Dr. Kasim Alomari (Presenter) Dr. John Gambatese, Oregon State University Dr. Ahmed Albayati
In addition to its risky nature, the construction industry incorporates a social interaction aspect as one of its qualities. The study presented in this paper aims to investigate the interaction properties that impact safety issues on jobsites. To meet this objective, periodic observations of the work taking place on a building construction project were conducted. During the observations, tens of hours of video recordings of workers conducting their traditional jobs/tasks were taken. After the completion of the work, an analysis of the two-mode networks for the worker and design element interactions using the social network analysis method was conducted. Two design element cases were analyzed, the concrete slab and steel beam components of the structure. The analysis shows that the workers are highly connected when considering the worker-design element interaction. To some extent, this result confirms the impact of design elements on the risk level of a worker. In addition to investigating the risk results for different trades on the jobsite, this study is unique in that it is the first in construction safety research to develop and analyze two-mode networks on top of video observations. The construction community can benefit from this study by extending current knowledge of the interactions that might lead to indirect risks, and then planning the work in a way that prevents and/or controls these interactions.
Benefit/Cost Model for evaluating Prevention though Design (PtD) solutions
Nicholas Tymvios, John Gambatese
Mr. Nicholas Tymvios, Bucknell University (Presenter) Dr. John Gambatese, Oregon State University
Research has shown a significant association of construction fatalities with design decisions, and Prevention through Design (PtD) has been hailed as an effective tool for the prevention of injuries on construction sites by addressing hazards during the design phase. The European Union (EU) identified this link and in 1989 enacted legislation requiring member countries to start practicing PtD.
Attempts to enact similar legislation in the United States have failed, and efforts to encourage designers to practice PtD in the general construction industry have not been very successful. Previous research has shown that in order to generate traction for PtD, it is essential to target owners, since they are seen as the group with the most influence for PtD. More importantly, the method with which that interest for PtD can be generated is by proving the business case. An evaluation and comparison of benefits and costs can be instrumental to encourage owners to demand PtD practice from their designers.
This paper describes the use of a multi-criteria analysis decision tool to evaluate between PtD solutions and traditional construction using two test cases. The line items used in the decision making tool were developed using the Delphi method, and the test cases were evaluated using input from industry professionals.
Exponential Random Graph Modeling: A Promising Tool for Construction Safety Research
Kasim Alomari, John Gambatese, Ahmed Al-bayati
Dr. Kasim Alomari Dr. John Gambatese, Oregon State University Dr. Ahmed Al-bayati, Western Carolina University (Presenter)
The interactions between construction workers have been studied in many ways. However, network-based interactions are barely investigated. Additionally, the few attempts to study the influence of social network on construction safety research have not used inferential aspects. Accordingly, the present study investigates the application of Exponential Random Graph Models (ERGMs) in construction safety research. In this study, an exploration of ERGMs is introduced theoretically by explaining the basics of the modeling, and practically by introducing a case study to enhance the understanding of how ERGMs can be used. The research methods include a literature review and an analysis of visual data from a construction field. The results show that both approaches show it is possible to use ERGMs in safety research. Additionally, the findings suggest that there is a higher probability of having an unsafe condition (i.e., higher risk) in construction sites when there is higher connectivity. The contribution of this study is the introduction of a new inferential procedure for analyzing worker interactions on construction sites concerning safety.
Performance Indicators for Construction Safety Culture and Climate: A Comprehensive State-of-the-Art Study
ABDULAZIZ ALGHAMDI, Ahmed Albayati, Osama Abudayyeh
Mr. ABDULAZIZ ALGHAMDI (Presenter) Dr. Ahmed Albayati Dr. Osama Abudayyeh, Western Michigan University
Safety culture and safety climate have been of interest to researchers and practitioners since the tragic incident of the Chernobyl nuclear power station in 1986. Numerous research efforts have focused on expanding the industry understanding of these safety performance indicators. However, there still is a significant ambiguity over the definition and elements of construction safety culture and safety climate. It is also worth noting that both terminologies have been used interchangeably by many researchers, suggesting the need for more efforts to clarify this issue. Currently, there are several instruments that have been suggested to measure construction safety culture and climate. Yet, these instruments do not seem to appropriately account for the unique characteristics of the construction industry such as the continual change in the job site environment, the variety and diversity of specialty crafts working side by side, and the relatively short time projects. Accordingly, the goal of this study is to conduct a comprehensive investigation into the state of the art of safety culture and climate to assist in clarifying the vagueness in their definitions and the differences between them. The study has identified the performance indicators and suggests that the construction industry still needs more efforts to clarify and unify the definitions and elements of safety culture and safety climate. These findings will help in focusing future research efforts and in understanding the needed elements for properly evaluating construction safety culture and safety climates, which in turn will help in developing metrics that are relevant to the unique nature of construction sites.
Potential Implications of Job Cognitive and Physical Demand on Worker Safety: An Exploratory Study
Mohammed Azeez, John Gambatese, Ding Liu
Mr. Mohammed Azeez, Oregon State University Dr. John Gambatese, Oregon State University Mr. Ding Liu, Oregon State University (Presenter)
With all the technological improvements and innovation to facilitate the work of field workers, construction is still categorized as one of the most physically demanding jobs. Job nature and job requirements are often incorporated in research, including safety research, but studies have not explored what job nature and job demand mean. The construction industry is also cognitively demanding, where workers have to measure materials and objects, assess work conditions, review information and identify problems, engage in decision-making, and produce a product that follows standards. These cognitive abilities combined with the physical capabilities that construction work requires might be a beneficial vantage point to investigate and address accidents at work.
This research aims to address the knowledge gap in our understanding of job nature by conducting a meta-analysis of both cognitive and physical demands using publicly-available data. The initial hypothesis is that jobs with a higher demand level(s), whether cognitive demand, physical demand, or both, have an association with a higher chance of accidents at work. To demystify this hypothesis, a comparative study between jobs in different industries was conducted. The result indicates that there is an imbalance between the level of both the cognitive demand and the physical demand between industries. Such imbalance might be the cause for the higher number of injuries associated with these jobs.
Health and safety (3)
Correlations between interpersonal conflicts at work and construction safety performance: two Ontario cross-sectional studies
Yuting Chen, Brenda McCabe, Douglas Hyatt
Ms. Yuting Chen, University of Toronto (Presenter) Dr. Brenda McCabe, University of Toronto Dr. Douglas Hyatt
Interpersonal conflicts at work (ICW) has been widely regarded as a job stressor; relatively few research studies have been conducted to measure ICW in the construction industry, not to mention the comparison studies of the conflict level on construction sites over time. ICW mainly has two forms on a construction site: conflicts with supervisors (ICWS) and conflicts with coworkers (ICWC). This study compared the occurrences of ICWS and ICWC on construction sites and correlated ICW with safety incidents, based on two survey datasets collected from 2004 to 2006 (911 surveys) and 2013 to 2016Â (1281 surveys) on Ontario construction sites. Less ICW were found, compared with ten years ago. Positive correlations between ICW and safety incidents were confirmed for both datasets. Less work pressure reported on Ontario construction sites may explain the decrease of conflict level. Future study may focus on building conflict management scales and test their influence on ICW on construction sites.
EVALUATING DISABILITY MANAGEMENT PERFORMANCE IN THE CONSTRUCTION INDUSTRY USING METRICS
Rhoda Ansah Quaigrain, Mohamed Issa
Dr. Rhoda Ansah Quaigrain, University of Manitoba Dr. Mohamed Issa, University of Manitoba (Presenter)
The risk of a major injury or fatality in the construction industry is two and a half times and five times higher respectively than that in the manufacturing industry. The resulting costs of injuries and fatalities in the form of productivity losses, workers’ compensation insurance and other direct and indirect costs affect the profitability of construction organizations. This reinforces the need for effective health and safety disability management and the need to quantify safety and disability management performance. A research study has been initiated by the University of Manitoba Construction Engineering and Management Group and funded by the Workers’ Compensation Board of Manitoba (WCB) for that purpose. The study aims to evaluate DM in the construction industry and its relation to safety performance using leading and lagging indicators of performance. This paper specifically aims to propose and assess new disability management metrics specific to construction. The research entailed collecting disability management data from 4 Manitoban construction companies and assessing their performance. In all 12 disability management metrics were proposed, 5 of which were assessed in regards to the companies. In all, companies recorded high percentiles in their retuned to work rates for injured workers, with few unaccounted absences and gaps. The identification of such gaps in performance is critical in creating awareness and ensuring necessary solutions. The findings reiterate the need to better integrate disabled workers in the construction workplace to improve the safety of the overall organization. It also justifies further investments in DM to ensure related practices effectively accommodate disabled workers on site and in the field
Global Differences in Risk Tolerance Levels Among Construction Workers
Siddharth Bhandari, Matthew Hallowell, Wael Alruqi, Rico Salas
Dr. Siddharth Bhandari, Western Michigan University (Presenter) Dr. Matthew Hallowell, University of Colorado Mr. Wael Alruqi, University of Colorado at Boulder Mr. Rico Salas, University of Colorado Boulder
A critical component of maintaining safety is to ensure that workers feel uncomfortable partaking in risky behavior. An individual’s willingness to engage in unsafe behavior is measured as risk tolerance. Given its subjective nature, risk tolerance is challenging to manage. However, understanding and influencing risk tolerance is essential to promoting safe behavior and increasing adherence to policies and procedures. This paper empirically examines the differences in risk tolerance levels among construction workers with data from a survey administered with 12,323 workers from 19 countries. One-way ANOVA shows that workers from countries examined in the survey registered statistically significant differences in personal and work-related risk tolerance levels. Furthermore, there seems to be positive association between personal and work-related risk tolerance. These findings suggest that an individual’s personal risk tolerance may have a strong bearing on their willingness to engage with risk at work and personal and work-related risk tolerance levels may be very different across geography and culture. If an organization seeks to align or manage risk tolerance to an acceptable level, it should endeavor to understand personal and cultural factors that influence risk-taking behavior. Future research should investigate whether specific personality characteristics, social interactions, and organizational safety practices influence risk tolerance and shape workplace behavior.
High Performance and High Strenght Materials/ Wood product in civil engineering
A Landmark Concrete Arch Bridge with an Innovative Approach: Post-tensioned Tie Girders
Luiza Curzio, Shayan Farahani, Ahmed Abuzour, Tanzim Arefin, Sameh Salib, Khaled Sennah
Ms. Luiza Curzio, Ryerson University - Civil Engineering (Presenter) Mr. Shayan Farahani Mr. Ahmed Abuzour Ms. Tanzim Arefin Dr. Sameh Salib, Ryerson University Dr. Khaled Sennah, Ryerson University
One of the oldest datable arch bridges was the Mycenaean bridge in Greece, built approximately 1300 BC. The curved geometry enables arch bridges to transfer their weight and carried loads along its curved load path to supports; a simple yet a quite robust mechanism. This distinctive characteristic is what makes the arch bridges one of the most popular bridges of all times.Â For the present project, the Greater Toronto Area (GTA) needs a bridge to carry both pedestrian/bikers and vehicular traffic over a water stream that passes through a scenic valley/woods. The project investigates two superstructure alternatives; a Bow-string concrete arch bridge (as a high aesthetically pleasing structure) and a side by side CPCI Box Girders alternative (as a conventional design/construction bridge type). The design work is divided in two phases. The first phase (preliminary design) includes a simplified analysis, design and quantity/cost estimation of each alternative. A comparison is performed based on a criterion that accounts for various aspects such as cost, durability, aesthetic and traffic impacts. Due to the nature of the project site, the highly aesthetic requirements of a landmark structure as such, the arch bridge is chosen as the preferred alternative. The second project phase (detailed design) focuses on refinement of the applied loads and analysis to provide detailed design and drawings for the respective bridge. Through this phase and in order to optimize the design and costs of the arch bridge, a post-tensioning system is introduced to the arch tie girders. Such unique approach improves the bridge stiffness and induces both compressive stresses and upward deflection (camber) in the tie girders. This significantly reduces both the potential for tensioning/cracking and the final bridge deflection. In other words, it lessens the long-term repair/maintenance and improves the appearance of the bridge during its service life. The present paper details the subject project and the approach to optimize the cost along with improving the aesthetics, performance and the overall sustainability of the subject bridge.
A shape memory alloy-magnetorheological fluid core bracing system for civil engineering applications: feasibility study
shahin zareie, Shahria Alam, Rudolf J. Seethaler, Abolghassem Zabihollah
Mr. shahin zareie, The University of British Columbia (Presenter) Dr. Shahria Alam, University of British Columbia Dr. Rudolf J. Seethaler, University of British Colombia Dr. Abolghassem Zabihollah
The stability of civil infrastructure is one of the main challenges for structural designers, users, and decision makers at the government level. To keep the stability and functionality of structures against moderate and strong loads, extensive studies have been conducted to develop supplemental structural control systems, particularly bracing system, with the energy dissipation ability.
For instance, bracing systems fitted with friction dampers, and viscous fluids are mounted in structural frames to provide the structural integrity against possible damage. These kinds of bracing systems are passive devices. Furthermore, most of the existing active and semi-active supplemental system integrated with bracing systems are not able to return the system to the initial position (the recentering ability).. Therefore, in the past few years, new hybrid smart structural elements integrated with smart materials, shape memory alloy and magnetorheological fluid, have been developed to structural stability and enhance the recentering ability of structural elements in infrastructures.
In this study, a hybrid smart bracing system is introduced to partially dissipate the amount of energy and add the recentering ability to the structure. The new hybrid smart bracing element consists of the shape memory alloy (SMA) fitted with magnetorheological (MR) fluid in its core. This system is able to keep the integrity and enhance the dynamic behavior of civil infrastructure during seismic events. simplicity to implement, easy to install, low operation and maintenance costs, energy dissipation capacity, the recentering ability, and fast responses are counted as the advantages of the present hybrid smart bracing system.
Development of Bendable Concrete And Rigid Pavement Overlay Application
Omar Ragab, Safwan Khedr, Mohamed Abdel Mooty, Maram Saudy, Khaled Hashim, Ali Ahmed, Omar El Sherbini, Omar El-Kadi, Omar El Shazly, Ahmed Hassabelnabi
Mr. Omar Ragab, The American University in Cairo Dr. Safwan Khedr, The American University in Cairo Mr. Mohamed Abdel Mooty Dr. Maram Saudy, The American University in Cairo Mr. Khaled Hashim Mr. Ali Ahmed, American University in Cairo Mr. Omar El Sherbini Mr. Omar El-Kadi, The American University in Cairo Mr. Omar El Shazly, The American University in Cairo Mr. Ahmed Hassabelnabi, The American University in Cairo (Presenter)
Concrete is one of the most ubiquitous materials around the world, especially in the construction industry. However, its single downfall is its brittle nature, but this paper aims at making concrete bendable.
Engineered Cementitious Composite or ECC is a ductile fiber reinforced mortar that exhibits higher flexural capacity, higher deformation capability before failure, and significantly reduced crack width, opposed to conventional concrete.
The main factor contributing to these enhancements is the polyvinyl alcohol (PVA) fibers that have a high tensile strength and modulus of elasticity, which decrease the brittleness of conventional concrete. Other factors include the absence of coarse aggregates to ensure the homogeneity of the mix and the proper dispersion of the PVA fibers.
The mix design of the ECC proposed in previous work consists of Cement, Fly Ash, very fine sand, PVA fibers, water, and superplasticizer. However, to make it relevant to Egypt, this paper aims to replace the Fly Ash with much cheaper locally produced Silica Fume and hence, changing the mix design of the bendable concrete.
In this paper, the experimental program is to include tests to measure the flexure strength of prisms, obtain stress strain curves of cylinders, obtain tensile stress strain curves of dog bone shaped mold, and measure the performance through dynamic loading. This experimental program is to be conducted on various mixes, with the concrete mortar being the control mix that will be compared to that of ECC with Fly Ash, and ECC with silica fume at different Silica Fume percentages.
The expected outcome of these tests would show enhanced ductile and flexural properties of the ECC mixes containing Silica Fume and Fly Ash as compared to that of conventional concrete. Additionally, it is expected that the Silica Fume mixes will have similar characteristics in regard to tensile strength and flexural capability to that of Fly Ash; therefore, the locally produced Silica Fume is expected to be a more feasible and practicable ECC mix in Egypt.
Â ECC shows great promise to be applied in many aspects in the construction industry due to its ductile nature and energy dissipating properties; therefore, this paper plans to study the effect of using the ECC as a pavement overlay to extend the road service life. This is to be studied practically through an experimental model and finite element analysis of that model.
Evacuation Modelling Procedures for Improving Timber Fire Design
Bronwyn Chorlton, John Gales
Ms. Bronwyn Chorlton, York University (Presenter) Dr. John Gales, York University
Timber structures are undergoing a renaissance in Canada. Architects desire that the structures be left exposed, without encapsulation so as to exploit our natural psychological biophilia tendencies. This demand of leaving the timber members exposed and unencapsulated brings substantial challenges for the engineer to ensure fire safe design. International practice for unencapsulated timber structures has subsequently moved to consider an increase in the prescriptive fire rating required for this type of building to compensate for the calculated increase in subsequent fire load (a transient fuel load calculated on the basis of charring rates). This procedure, with limitation, negates the effects of ventilation and oxygen supply which will influence the timber’s actual contribution to the fire. Fire Dynamics aside for now, further the argument is made that the required fire rating is increased on the premise of allowing for safe evacuation owing to the additional fire load present. Herein, the authors consider the basis of evacuation modelling that can be tailored specific to the occupancy type as well as a quantifiable study of the fire risk of exposed timber. When these are considered, evacuation times can actually be lowered and therefore when assessed in parallel to the timber’s increased fuel load, the increased fuel load is not a hindrance with respect to egress situations to ensure safety. An accurate demonstration of an alternative design solution then becomes achievable. Within the proposed manuscript, the authors provide a hypothetical tall timber structural and architectural Canadian design which takes into account the increased needs for accessibility of its occupants for emergency egress. This evacuation analysis, which is based upon realistic protective action decision making methodologies developed by the authors to speed pre evacuation, demonstrates that egress speeds faster than the prescriptive requirement are observed when accessibility needs are thoroughly addressed, increasing safety without compromising the exposed timber spaces. The paper will provide a comparison between typical European and Canadian design guidance for tall timber fire safety (evacuation and coupled fire dynamics in a timber structure), as well as establish a framework of research in order to promote design solutions for tall timber construction in Canada.
Finite-Element Modelling of Ductile Wood Connections
Asif Iqbal, Petr Sejkot
Dr. Asif Iqbal, University of Northern British Columbia (Presenter) Dr. Petr Sejkot, Kolkner Institute
Typical connections in wood structures consist of structural members connected with thin-walled steel elements, commonly angle brackets. The design of these steel elements is typically based on short-term load bearing capacity experimental testing. Experiences from the experimental testing indicate that both steel plate and connectors possess properties such that these connections can be designed to behave in ductile manner. Following the capacity design principle, during seismic loading the structural members remain undamaged while the damage and most of the energy dissipation is confined within the steel elements. However, there is insufficient support in Building Design Codes to design any building for a seismic situation in such a manner. This paper presents development of numerical models of the connections and subsequent validation by experimental results. Their applications in replicating performance of a number of metal bracketed connections with these characteristics are illustrated. Two sources of ductility for the overall arrangement, namely deformations in the metal connectors and in nails (bending and pulling out) due to cyclic loading have been identified. The steel plate absorbs significantly less energy after the first circle while the nails can dissipate energy more consistently over the cycles, characterized by pinching and elasto-plastic behavior respectively. The models offer insights into detailing ductile connections in wood and possibility in the optimization of the connectors for seismic design.
Numerical investigation of concrete-filled steel square columns subjected to concentric and eccentric loading
Soebur Raham, Kamrul Islam, Ibriju Ibrahim, Aziz Ahmed
Mr. Soebur Raham, Military Institute of Science and Technology Mr. Kamrul Islam, Ecole Polytechnique de Montreal (Presenter) Mr. Ibriju Ibrahim, Military Institute of Science and Technology Dr. Aziz Ahmed, University of Wollongong
Concrete filled steel tubular (CFST) column is a type of composite column where the concrete core is fully encased by steel section of different shapes. CFST column has garnered popularity due to its beneficial mechanical properties such as high strength, stiffness and ductility. In addition, CFST column enhances the overall rigidity of the structure and provides significant shear resistance to strong earthquakes and other lateral loads. This paper presents the details of an experimental investigation on fifteen CFST stub columns made with built-up section. The test specimens were fabricated by metal arc welding from hot-rolled channel section of nominal thickness 4 mm and 5 mm. All the fifteen stub columns were tested in pure axial compression. Moreover, four hollow stub columns with two different sizes were tested. The variable parameters for the experiment were concrete strength, cross sectional dimension and thickness of the steel section. Three different concrete strength, 30 MPa, 40 MPa and 50 MPa were used in this study. Both tensile and compressive material properties were obtained by means of coupon tests and concrete cylinder tests. The main objective of this research work is to study the behavior and the cross-sectional capacity of CFST stub columns made with built-up sections. The failure modes and load–end shortening behavior of the CFST columns were investigated. The experimental results were compared with the existing AISC-2013 and EC4 design guideline which clearly show the conservative nature of code predictions. The experimental investigation was complemented by finite element (FE) modelling using ABAQUS. Numerical models were validated using the current experimental data and the available test results in the literature. The FE models predicted the experimental load-deformation curve, ultimate strength and failure modes with good accuracy.
Potential Use of heavy weight concrete for radiation shielding
Mostafa Seoudi, Kareem El-Shafei, Omar Hammouda, Aya El Desouky, Hossam Zaher
Mr. Mostafa Seoudi, The American University In Cairo (Presenter) Mr. Kareem El-Shafei Mr. Omar Hammouda Ms. Aya El Desouky Mr. Hossam Zaher
The world has been gradually shifting towards the use of nuclear power plants to produce conventional fossil energy. As expected, these power plants emit a spectrum of radiation that can cause, when leaking, serious harm to human being as well as serious damage to the structure and its surroundings. This study stems from this background in an attempt to produce adequate concrete with effective radiation shielding. In this study, a set of heavyweight aggregates were selected to be incorporated to replace both coarse and fine aggregates aiming at reaching sound concrete mix. These aggregates include granite, basalt and slag as coarse aggregates as well as iron powder, slag powder and direct reduced iron (DRI) as fine aggregates. The aggregates were subjected to rigorous testing including Energy-dispersive X-ray Spectroscopy test to determine the elemental analysis and ensure that they have a high metal content that can serve in blocking the radiation atoms and reduce their energy. The heavyweight concrete mix are tested for fresh and hardened as well durability testing. Most importantly, all mixes were evaluated for radiation shielding through the use of Gamma Ray Point source and detector using various thicknesses and different times to determine the attenuation coefficient for each mix. This coefficient can show the radiation shielding properties for each mix and hence classifying such potential protection. Concrete samples are exposed for longer durations to a gamma source to identify any loss in mechanical properties. This should help show the effect of radiation exposure compared to the mechanical properties of the unexposed samples. Recommendations are made as to how to select suitable constituents aiming at achieving radiation shielding for various applications.
Seismic performance analysis of high-rise RC shear walls reinforced with superelastic shape memory alloys
Marina Maciel, Wilmar Leonardo Cortes Puentes, Dan Palermo
Ms. Marina Maciel, York University (Presenter) Mr. Wilmar Leonardo Cortes Puentes, University of Ottawa Dr. Dan Palermo, York University
A study is currently in progress to investigate the seismic performance of hybrid SMA-steel shear walls containing NiTi superelastic shape memory alloy (SMA) as an alternative reinforcement in the plastic hinge zone. This type of wall system provides self-centering with high levels of energy dissipation due to the hysteretic response characteristic of cyclically loaded SMA bars. The main benefit is the significant reduction of permanent deformations due to the shape recovery of the SMA. The introduction of NiTi bars in the plastic hinge region of the shear wall, where large inelastic deformation demand is concentrated, optimizes the seismic performance of reinforced concrete buildings, controlling residual deformations and thereby reducing the damage to non-structural and structural elements. This study considers two design earthquake scenarios for a prototype 10-storey office building: a moderate seismic zone in eastern Canada and a high seismic zone in western Canada. Traditional deformed steel-reinforced shear walls were designed for each seismic zone, corresponding to ductile and moderately ductile shear walls for western and eastern Canada, respectively. The resulting cross-sections were used to define the reinforcement layout of the hybrid SMA-steel shear walls. Thereby, the walls are comparable in terms of geometry and reinforcement ratio, and a reliable comparison of the post-earthquake condition (i.e. residual displacements, drifts, dissipated energy, displacement capacity) is thereforeÂ possible. To determine important features of the seismic response, full-scale 2-D finite element models of both types of walls were developed and subjected to pushover and reverse cyclic analyses. The use of a detailed finite element analysis permitted an explicit evaluation of damage, including cracking of concrete, strain and deformation of reinforcing steel and SMA. The paper presents results of the analyses and the assessment of the seismic response of the hybrid SMA-steel wall compared to the steel-reinforced wall. Expected results include similar capacity due to the use of equivalent reinforcement, slightly lower energy dissipation given the flag-shaped hysteretic response of SMA and superior restoring capacity of the hybrid-SMA wall. This study will culminate with nonlinear time-history analyses performed with a suite of earthquake records. The selection of the earthquake records will consider the magnitude, epicentral distance and frequency content characteristics of each seismic zone. Therefore, the influence of earthquakes in moderate and severe seismicity on the seismic response of the walls and the potential improvements in self-centering capacity of hybrid SMA-steel walls will also be assessed.
A LABORATORY STUDY OF THE EFFECT OF ACOUSTIC DOPPLER VELOCIMETER SAMPLING FREQUENCY AND SAMPLING VOLUME ON MEASUREMENTS
Babak Khorsandi, Laurent Mydlarski, Masoud Moeini, Mohammad Kazemi
Dr. Babak Khorsandi, Amirkabir University of Technology (Tehran Polytechnic) (Presenter) Dr. Laurent Mydlarski Mr. Masoud Moeini Mr. Mohammad Kazemi
Acoustic Doppler velocimeters (ADVs) are popular devices for the measurement of velocity in hydraulic engineering applications. It has been found that ADVs accurately predict the mean velocity; however their turbulence measurements is affected by noise. It is expected that the turbulence measurements is further influenced by user adjustable ADV parameters, such as the sampling frequency and sampling volume. These parameters affect how the ADV outputs velocities (by the temporal and spatial averaging). Given this, an experimental work focusing on the performance of ADV operating at different sampling rates and sampling volumes has been conducted to evaluate how the turbulence statistics may be affected. The velocity field of a turbulent axisymmetric jet with a Reynolds number of 10,000 issued into a background of quiescent water was measured via an ADV. Measurements of the mean and RMS velocities at different sampling frequencies and sampling volumes were conducted and compared with those of other measurement techniques. The results show that mean velocities were not influenced by variations in neither the sampling frequency nor the sampling volume. On the other hand, the RMS velocities were damped as the sampling frequency decreased (resulting in more pings being averaged) or when the sampling volume increased (resulting in the velocity being averaged over more scattered particles). The present results offer an opportunity to choose proper sampling frequency and sampling volume for the ADV in measurements of turbulent flows.
Can a Vortex Improve Flow Conditions in a Stormwater Retention Pond or a Clearwell?
Rocky Chowdhury, Kerry Mazurek, Gordon Putz, Cory Albers
Mr. Rocky Chowdhury, City of Meadow Lake Dr. Kerry Mazurek, University of Saskatchewan (Presenter) Dr. Gordon Putz, University of Saskatchewan Mr. Cory Albers, Source2Source Inc.
Both stormwater retention ponds and clearwells are large, open storage reservoirs a few meters in depth. Both originally were designed for water storage without much consideration to the flow dynamics through them. In each case, the residence time of the flow in the reservoir is important. For retention ponds, longer residence times provide time in the pond for settling of solids and treatment of pollutants before the stormwater is discharged into receiving streams. Clearwells, used in water treatment plants, need a long contact time for the disinfectant that is injected in the water flow to react before the water enters the distribution system. Both often suffer from poor flow dynamics with short-circuiting and dead space, which reduce treatment times. To improve performance, it is sometimes necessary to modify the flow behavior. These modifications are often done using baffles. This paper investigates whether or not modifying the typical flow path in a reservoir to a large vortex will improve performance. Tests were carried out in scale models of a 50 and 100 m diameter circular cells with each of 2 m depth, where there was a radial inflow and a central outlet. The residence time distribution was evaluated using tracer studies for varied flow rate and time of initiation of flow in the model. Observations showed that although dead space was relatively small (mostly near 2 %), however, the time of first observation of dye was unexpectedly early because of a secondary flow component that was produced in the overall flow, which resulted in a radial inflow near the bed towards the outlet. It appears that if the secondary flow can be prevented, the vortex would provide an excellent option for improving residence times in these types of reservoirs.
Characteristics of Flow over the Crest of a Siphon Spillway
Warda Ahmed, S. Samuel Li, Amruthur Ramamurthy
Ms. Warda Ahmed, Concordia University (Presenter) Dr. S. Samuel Li, Concordia University Dr. Amruthur Ramamurthy, Concordia University
Abstract: Siphon spillways provide a highly efficient control of flow with a small increase in the reservoir water level. Flow over the circular crest of a siphon is highly curvilinear. In fact, curved flows are common in hydraulic engineering applications. It is important to achieve a good understanding of curved flows. The purpose of this paper is to study the characteristics of curvilinear flow over a siphon spillway in the regain of a rounded-crest. The siphon structure has fixed upstream and downstream slopes. To investigate the curvilinear flow over the crest, theoretical analysis and numerical modelling were performed. The theoretical analysis was conducted to determine distributions of streamlines and the radii of curvature of the streamlines. The theoretical analysis uses curvilinear coordinates. The Dressler equation was used to mathematically study the flow at the crest regain. The Dressler equation is significant in flow analysis. It has been used to solve many hydraulic problems involving curved surfaces. Furthermore, we obtained discharge coefficient values for the siphon spillway from the theoretical analysis and compared them with existent experimental results. The flow field was obtained using Computational Fluid Dynamics (CFD) model for the case of submerged flow. The model results give flow velocities in three dimensions covering the geometry of the siphon spillway. For computations of multiphase flow velocity and pressure distributions, a range of Reynolds number values are considered. The computations use the RNG k-? model for turbulence closure. The RNG k?? model is proven to have high accuracy for simulations of turbulent flow, especially in domains with curved boundaries and wall boundary layers. The CFD model predictions are validated with using results obtained from momentum analysis and theoretical siphon model. The results from the current study shed light on such characteristics of the flow past the siphon crest as the discharge coefficient, velocity distributions, and pressure distributions. It is shown that the pressure on the siphon crestâ€™s low surface is negative and therefore could lead to the occurrence of cavitation. The results show that the flow field computed by using the RNG k-? model matches well with the data from the momentum analysis. There is a reasonable agreement between the computed and theoretical values of distributed pressures and velocities.
ESTIMATION OF INSTREAM FLOW NEEDS FOR RIVERINE FISH AND FISH HABITAT IN LOW-SLOPE RIVERS
As fish habitats represent some of the most difficult biological, topographic and hydrodynamic phenomena to evaluate, estimation of environmental flows or instream flow needs for fish and fish habitat becomes a challenging process to assess in details. However, hydrodynamic models with habitat simulation features may now provide one tool to examine and analyze the quality and quantity of complex fish habitats in such challenging circumstances with reasonable accuracy. The purpose of this study was to estimate the instream flow needs that can be used to protect or enhance the fish and fish habitats in three sites of three low-slope Rivers in Canada. The River2D hydrodynamic model combined with fish species-specific habitat suitability criteria was used to achieve these goals. The model was used to predict channel hydraulic or physical habitat characteristics, mainly velocities, water depths and water levels. Model predictions were presented for a wide range of flows. The hydrodynamic model results, coupled with the biologically significant suitability metrics, were used to determine changes in fish habitat use areas with discharge, estimate weighted usable areas, and consequently estimate instream flow needs or environmental flows for several fish species. This ichthyohydraulic simulation process provides water management guidance to protect or enhance fish and fish habitats in these rivers.
Numerical Modelling of Nature-like Fshpass using a 2D Shallow Water Model
Abul Baki, Amir Golpira, Cassio Rampinelli, Lukas Patrizio, David Zhu
Dr. Abul Baki, Clarkson University (Presenter) Mr. Amir Golpira Mr. Cassio Rampinelli Mr. Lukas Patrizio Dr. David Zhu, University of Alberta
Flow around fish habitat structures (e.g., boulder, rock) is of great interest, particularly for ?sh passage technology. Modelling such three-dimensional (3D) complex hydraulics associated with a habitat structure using an industrial 2D code solving Saint Venant equations may appear at ?rst as a challenge. The purpose of this study is to determine the ability of a 2D code (River2D) to model ?ow through rock-ramp type nature-like fishpass and its limitations. The model was tested based upon the comparison between numerous experimental measurements and numerical simulations. The impact of varying computational mesh discretization on the accuracy of simulating velocities and water-surface elevations was investigated using the River2D model. The results demonstrate that 2D shallow water modelling using an industrial code River2D can be a convenient way for the hydraulic engineer to help design a nature-like ?shpass. Finally, the performance of rock-ramp ?shpass is discussed in the context of ?sh resting zones, volumetric dissipated power, fish kinematics/energetics, and ?sh swimming performance.
Comparison of four input variable selection methods for urban riverine flood forecasting models for the Bow River
Everett Snieder, Usman Khan, Rahma Khalid
Mr. Everett Snieder, York University (Presenter) Dr. Usman Khan, York University Mrs. Rahma Khalid, York University
Flood risk and vulnerability in cities are expected to increase in coming years due to climate change and rapid urbanization. Flood damage can be mitigated using early warning systems, which provide emergency services with an advanced notice of flood likelihood. In recent years, machine learning has been demonstrated as a suitable approach for modelling complex hydrological processes, including flood forecasting. While the use of machine learning models has been widely investigated in recent years, relatively little attention has been given to model Input Variable Selection (IVS) for these models. IVS is overwhelmingly reliant on expert knowledge and ad-hoc approaches, rather than objective approaches to obtain the best performing model.
This research uses Artificial Neural Networks (ANNs), a common machine learning model in hydrology, to generate flow forecasts of 1, 2, and 3 days ahead, for the Bow River in Calgary AB. The model considers a set of candidate input variables including mean, maximum, and minimum upstream flow, downstream flow, and temperature, and daily precipitation. Three lag times are included for each unique candidate input.
IVS methods are used to reduce the input candidate set to an optimal subset. This research compares two well established IVS methods, Partial Correlation (PC) and Partial Mutual Information (PMI), and two relatively uncommon methods, Combined Neural Pathway Strength (CNPS) and Input Saliency (IS). These methods are compared to each other based the performance of the ANNs they inform.
Preliminary results indicate that all four IVS methods are adequate in reducing the number of inputs from 30 to 6 without significant losses in model performance; the PC informed models exhibit the worst performance and the PMI informed models, the most favourable. Next, there is notable variance amongst the number of inputs determined by each selection criterion. Collectively, this indicates that while distinct IVS methods may be capable of ranking input variable importance, the selection criterion is more important.
This research demonstrates the nuances between different IVS methods and underlines the necessity of reliable and systematic input reduction in the development of ANN models. Additionally, validating model-based IVS methods (CNPS and IS) may help to directly attribute physical meaning to ANNs, as the absence of a physical basis is a common criticism of machine learning. Upcoming research topics include assessing the sensitivity of each termination criterion and cross-validating these findings with other hydrological systems or synthetic datasets.
High-Resolution Projections of Temperature Changes over China
Yinghui Wu, Gordon Huang, Xiujuan Chen
Mr. Yinghui Wu, IEESC, University of Regina (Presenter) Dr. Gordon Huang, University of Regina Ms. Xiujuan Chen, University of Regina
Planning of mitigation and adaptation strategies to the changing climate is of great significance to China, due to its large population and fast growing economy. This study presents a high-resolution regional climate simulation for China using the Weather Research and Forecasting (WRF) Model. A historical simulation from 1980 to 2005 was performed and validated, while for the future two simulations from 2006 to 2099 were performed under two emission scenarios (i.e. RCP 4.5 and RCP 8.5). The projections indicate that China is likely to suffer a significant temperature rise by the end of the century, with greater changes and uncertainties under RCP 8.5. The presented study could provide decision support for the policy making of mitigation and adaptation strategies.
Preservation of ecological indices in downscaled climate data
Diana Sankar, Joseph Daraio
Ms. Diana Sankar Dr. Joseph Daraio, Memorial University of Newfoundland (Presenter)
The effects of climate change are likely to have a significant impact on environmental flows, which are often represented by hydrologic and ecological indices. These indices represent relationships between the ecology of a waterway and the five primary flow statistics: magnitude, frequency, duration, timing and rate of change. Changes in flow regimes caused by climate change have implications for river ecology, and projections of future flow regimes must be reliable and uncertainty must be quantified in order to determine strategies to maintain environmental flow needs in the future. To assess the potential impacts of climate change on important indices, downscaling of general circulation models (GCM) is required to use climate change projections in hydrologic models because of the spatial mismatch between GCM output data and meteorological data required to drive hydrological models. There are a variety of downscaling methods and choice of method depends on the scale of the hydrologic application. The objective of this research was to determine which downscaling method is most appropriate when determining environmental flows and ecological indices.
Two watersheds in New Jersey located within the Pinelands ecoregion, an ecologically sensitive area with many endangered and threatened species, were used in the analysis. Ecological indices were calculated for the Batso River Watershed (a undeveloped watershed) and the Maurice River watershed (a developed watershed) and were analyzed using different downscaling methods, dynamic and statistical (change factors), to determine which downscaled method best preserved historical ecological indices and determined future indices.
Preliminary results using observed USGS stream flow data and the hydroecological integrity assessment process indicated that dynamically downscaled data does not preserve ecological indices. Results also suggest that the change factor method, a simpler and less computationally intensive tool can be used instead when determining ecological indices for future conditions.
Temperature controls of the freeze and thaw patterns in Quebec
Shadi Hatami, Ali Nazemi
Mrs. Shadi Hatami, Concordia University (Presenter) Dr. Ali Nazemi, Concordia University
Accurate quantification of Freeze and Thaw (FT) dynamics is essential for better understanding of environmental processes and socio-economic activities across cold regions. However, climate variability and change can significantly perturb the characteristics of FT patterns, which can in turn result in profound alterations in land-surface characteristics. Investigating the control of temperature on FT is therefore an important step toward advising effective adaptation strategies for future human developments at higher latitudes. There are, however, a number of deficiencies associated with in-situ measurement of FT in terms of temporal and spatial extent of data as well as limitations in extending the local data to regional knowledge. To avoid these gaps, we use gridded remotely sensed FT data record and pair them with gridded surface air temperature data to quantify the association between climate and FT patterns across Quebec during 1979 to 2016. We study the joint dependence between temperature and FT patterns analyze its variability over time and space. The copula methodology is employed to formally quantify temperature control on FT dynamics, which provides a generic tool for assessing the future FT according to future projections of temperature. Considering the changes in copula parameters, we address the role of geographic characteristics on altering the temperature control on FT.Â
The existence of useful varying parameter space for river flow forecasting
Mohammad Alobaidi, Mohamed Meguid, Fateh Chebana, Mohammed Elenany, Bahaa Khalil
Dr. Mohammad Alobaidi, McGill University (Presenter) Dr. Mohamed Meguid, McGill University Dr. Fateh Chebana, Eau Terre Environnement, Institut National de la Recherche Scientifique Dr. Mohammed Elenany, Urban Systems Ltd., Canada Dr. Bahaa Khalil, Helwan University, Egypt
River flow modeling and forecasting studies have been dominated by statistical and heuristic based techniques. Such Techniques are shown to successfully produce useful inferences in absence of information on the variables that drive the evolution of the flow, of which a useful subset is typically utilized for physically inspired forecasting models. Like any time series generated by complex systems, river flow evolution can be represented by a time-varying parameter (TVP) model. TVP modeling frameworks often assume that the system evolution exhibits superstatistical random walks, and a statistical cohort of other assumptions is followed upon, to infer better forecasts about the system. Also, the TVPs should hone a predefined model ability to capture systems recurrence, which translate to a number of state-based model structures in this case. To the best of our knowledge, there has been no research effort made for assessing the possibility of modeling river flows on extended horizons and more continuously. In this work, we develop a computationally efficient method that extracts useful cyclic-type TVPs that are strongly coupled over extended, but more continuous and less aggregated, time horizons. A multi-level modeling framework is suggested to facilitate the creation and direct use of updated parameter states to produce reliable models on the considered temporal resolutions. We also show that the modeling framework produce stable results of the parameter variations at different time strings. The proposed framework have can incorporate exogenous descriptors at different levels without loss of generality, and can be used in forecasting applications.
Keywords: River flow forecasting; varying parameter framework; system identification; clustering
Industrial Wastewater Treatment
An Agent-Based Stochastic-Probability Simulation Modeling for Chemical Reactions in Advanced Oxidation Processes â€“ A Case Study
Xudong Ye, Bing Chen, Jisi Zheng, Bo Liu
Mr. Xudong Ye, Memorial University of Newfoundland (Presenter) Dr. Bing Chen, Memorial University Mr. Jisi Zheng, Memorial University Mr. Bo Liu, Memorial University of Newfoundland
Advanced Oxidation Processes (AOPs) have been defined as emerging wastewater treatment technologies with the generation of highly radicals (esp. hydroxyl radical). These processes can effectively handle various hazardous organics in wastewater and groundwater. This study developed a novel agent-based stochastic-probability simulation modeling to reflect the interactive reactions from a microscopic perspective and predict the outcomes under different chemical concentrations. The developed method simulated the chemical reaction networks of AOPs within a spatial resolution to molecule size scale. Each molecule was treated as a point-like particle that diffused freely in a three-dimension space. When a pair of reactive molecules collided, a reaction occurred based on the reaction probabilities and kinetic parameters, the simulated reactants were then replaced by products. More than 20 basic reactions in AOPs system were considered and the input to the simulation are from NRPOP experimental data and previous journal papers. The model can simulate AOPs with more than 200,000 particles (including reactants and intermediates) within both short-term (hours) and long-time (days) periods. The preliminary results showed approximate trends (e.g., Organic matter, hydroxyl radical) in the comparison with the experimental result curves. The capacities of the proposed method will be subsequently demonstrated with the case studies considering five types of AOPs are considered: ozone, ozone with hydrogen peroxide, UV photolysis of ozone, UV photolysis of hydrogen peroxide, and UV photolysis of ozone and hydrogen peroxide. The simulated results will be further compared with experimental data by correlation analysis.
CASE STUDY: EVALUATION OF PURE AND MIXED BACTERIAL CULTURES ON SULFOLANE BIODEGRADATION IN AQUEOUS MEDIA
Yiqiao Yang, Linlong Yu, Gopal Achari
Ms. Yiqiao Yang, University of Calgary (Presenter) Dr. Linlong Yu, University of Calgary Dr. Gopal Achari, University of Calgary
Sulfolane (C4H8SO2) is an organosulfur compound with high water solubility and low soil adsorption. In the early 1960s, it was first introduced to western Canada as a solvent to perform sour gas sweetening (SulfinolR process) and aromatics extraction from hydrocarbon mixtures in the oil and gas industry. However, lack of control on the disposal of sulfolane containing waste during the past half century has resulted in groundwater and soil contamination near natural gas refinery plants. Off-site contamination was also reported as a result of sulfolane’s high mobility in water. Due to the widespread sulfolane contamination in North America and its potential health hazard toward human, there is a need to develop a method that remediates sulfolane contaminated water and soil.
Among the various sulfolane remediation technologies, aerobic biodegradation provides the most efficient and economical solution in removing sulfolane from aqueous media. With past researches mainly focused on the application of in-situ microbes to treat sulfolane, it is possible the sulfolane aerobic biodegradation process can be expedited by using single species of microbe. This paper evaluates the sulfolane degrading performance of two microbial species namely pseudomonas and archaea. Their efficiency of treatment was also compared with aquifer sediments contain a mixture of sulfolane degrading microorganisms. In addition, both microbes were modified through introducing amendments and acclimatization to enhance their sulfolane degrading performance.
Experimental results have shown that sulfolane can be effectively removed from aqueous media using single species of microbe. Comparing the two single species of microbes with aquifer sediments, pseudomonas exhibited the fastest sulfolane degradation rate. Modification study shows microbes’ sulfolane degradation rate can be accelerated through the addition of amendment, and lag times before the onset of sulfolane biodegradation can be reduced after acclimatization.
Effect of Substrate Composition on Anaerobic Digestion under Mesophilic Conditions
Laura Cordova Villegas, Rajan Ray, Rajesh Seth, Nihar Biswas
Dr. Laura Cordova Villegas, University of Windsor Dr. Rajan Ray, University of Windsor Dr. Rajesh Seth, University of Windsor (Presenter) Dr. Nihar Biswas, University of Windsor
Energy supply and environmental protection are two crucial issues for the sustainable development of global prosperity. Anaerobic digestion is a well-known process to produce biogas from different municipal wastes and can be a solution for energy shortage. Wastewater can vary in composition, but the main types of compounds present are carbohydrates, proteins and lipids. A laboratory scale study using semi-continuous batch reactors with multiply cycles was done to understand the effects of different substrates: starch (model compound for carbohydrate), bovine serum albumin (model compound for protein) and acetic acid (model compound for lipids) and a mixture of all of them on the composition on biogas yield. Experiments were also carried out to determine the changes in acclimatization of methanogens for the targeted substrate using sludge from municipal wastewater treatment plant digester. For a fixed 0.5 g COD/ g VSS feed, bovine serum albumin showed a maximum 250 Nml gas production within 7 days of HRT. Mix, acetic acid and starch followed by 8.5, 9 and 10 days after 3 cycles, respectively. However, after the acclimatization of methanogens, the time to produce the maximum yield reduced to 5, 6, 6.5 and 7.5 days for protein, mix, acetic acid and starch after 6 cycles, respectively. The difference of rate for maximum gas productions was as follows: protein?mix>lipids?carbohydrates. Also, it was determined that the mix was the combined effect of each substrate; where each substrate contributes in the same proportion to the gas production.
Graphene- Titanium Dioxide Composite: A Novel Photocatalyst for the Degradation of Emerging Organic Contaminants
Sripriya Dharwadkar, Linlong Yu, Gopal Achari
Ms. Sripriya Dharwadkar, Univeristy of Calgary Dr. Linlong Yu, University of Calgary Dr. Gopal Achari, University of Calgary (Presenter)
Photocatalysis is an advanced oxidation process (AOP) that uses light energy to activate a substance known as a photocatalyst, which then triggers a series of reactions that breakdown organic contaminants in water. Photocatalysis offers the possibility to harness sunlight, posing as a low cost and energy saving approach for treating organic contaminants from water. Titanium dioxide (TiO2), the most commonly used photocatalyst, can be excited by photons with wavelengths shorter than 385 nm. Only 5% of solar radiation received by the earth’s surface accounts for this spectrum of wavelengths. Therefore, there is a demand for photocatalysts that can be activated by light with longer wavelengths in order to maximize the use of sunlight. Combining photocatalysts with graphene has been shown to enhance the performance due to its strong adsorption capacity, photocatalytic activity and overall stability. Graphene based photocatalysts have been used to effectively remove many water-borne organic dyes under visible irradiation. However, this application has not yet been extended for use in emerging contaminants.
In this study, composites of graphene and titanium dioxide (Gr-TiO2) were synthesized using the hydrothermal method, where graphene oxide is reduced to graphene and simultaneously deposited onto the TiO2 surface. The effectiveness of Gr-TiO2 was then evaluated by testing its use in the removal of organic dye (methyl orange) and emerging contaminants. Both ultraviolet A(UVA)-LED and blue LED were used for experiments as the source of irradiation. Light emitting diodes (LED's) are a novel and robust light source that offer better energy utilization than conventional mercury lamps. Sulfolane and phenol are selected as candidates for emerging contaminants in these experiments. Sulfolane is a solvent used to remove acidic component from sour natural gas and has been reported to contaminate soil and water near gas plants in North America. Phenol is a precursor for many chemical products and causes adverse effects to biota when released into aquatic environments.
The results show that the performance of Gr-TiO2 varied for each contaminant and light condition. Gr-TiO2 can effectively degrade sulfolane and phenol with UVA irradiation, but barely any degradation was observed using the blue light. Further investigation indicated that Gr-TiO2 showed better performance than powdered TiO2 in dye removal. However, powdered TiO2 exhibited better overall performance for the degradation of sulfolane and phenol than Gr-TiO2.
Reuse of MBR Effluent from Fruit Processing Wastewater Containing High Dissolved Organic Matter
Jamal Uddin, Richard Zytner, Keith Warriner, Ashutosh Singh
Mr. Jamal Uddin, School of Engineering/U of Guelph (Presenter) Dr. Richard Zytner, School of Engineering, University of Guelph Dr. Keith Warriner, School of Engineering/U of Guelph Dr. Ashutosh Singh, School of Engineering/U of Guelph
Reuse of wastewater is a recognized approach to enhance sustainability of resources within a water management program. Literature shows that limited work has been done on the reuse of wastewater from the fruit processing industry (FPI) despite the sector being a heavy water user. One of the challenges is the varied strength and composition of FPI wastewater that ultimatly leads to instability in the membrane bioreactor (MBR) during wastewater treatment and fouling of downstream systems like a reverse osmosis (RO) unit.
The passage of low molecular soluble microbial products (SMP) and extracellular polymeric substances (EPS) components through the MBR membrane system, results in high dissolved organic matter (DOM) loading in the effluent. Operating parameters such as temperature, pH and dissolved oxygen, along with a change in fruit type, promote a shift in the metabolic capacity of the sludge within the reactor leading to a lack of reduction in DOM. Typical analysis of MBR effluent at different dates showed a composition of 5-10 ppm protein, 20-40 ppm carbohydrate and 50-70 ppm humic substances. Correlation with TOC measurement and subsequent standard graphs exhibited more reliable prediction on different EPS components. These products along with unidentified organics foul the downstream RO membrane, making the recycle process difficult. Results showed a 85% flux decline after only 75 h of continuous operation when DOM was 80 ppm. Online membrane management could only improve permeation by 10%, with the flux continuing to decline to about 90% over the next 25 h of operation. Foulant analyses using SEM-EDX and FTIR revealed major inorganic functionality on the surface of the membrane.
Experiments were completed to resolve this critical DOM issue. Various techniques at different scale/doses were investigated using 5 different GAC, 5 different coagulants and 3 coagulant aids. Finally, enhanced coagulation using high dosed alum and ferric chloride coupled with chitosan flocculation was found successful, with substantial reduction in the effluent DOM through liquid phase amorphous adsorption followed by solid phase sorption on the GAC surface. The effluent DOM was reduced to about 6 ppm, achieving a positive 93% reduction. Subsequent bench operations using the pretreated effluent as RO feed showed encouraging results without any flux decline. On-going work is evaluating long-term options for continuous operations that include bio-fouling monitoring, membrane cleaning and performance restoration. The paper will discuss in detail the best management practice (BMP) findings to encourage the sustainable recycling of FPI wastewater.
TREATMENT OF PRODUCED WATER USING MICROFILTRATION MEMBRANE MODIFIED BY NANO PARTICLES
Xiujuan Chen, Gordon Huang, Yinghui Wu, Chunjiang An
Ms. Xiujuan Chen, University of Regina (Presenter) Dr. Gordon Huang, University of Regina Mr. Yinghui Wu, University of Regina Dr. Chunjiang An, Concordia University
Membrane filtration technology has been considered as a promising alternative for produced water treatment. However, membrane fouling is a critical problem that affects wastewater treatment efficiency. Membrane surface modification has been regarded as an effective method to improve membrane antifouling ability. In this study, a novel membrane surface modification method was proposed to obtain a super-hydrophilic membrane with high water permeability and great oil rejection through cold plasma-induced PAA graft-polymerization followed by nano-ZnO self-assembly. The results indicated that a PAA layer was uniformly formed on the membrane surface, and ZnO nanoparticles (NPs) were strongly immobilized by the PAA layer. The firm PAA-ZnO coating on membrane surface brought about dramatically improvements of membrane performances both in permeation flux and pollutant rejection rate.
Assessment Approach to Evaluate the Conditions of Ductile Iron (DI) Water Distribution Pipelines
Khalid Kaddoura, Alain Lalonde, Rabia Mady
Dr. Khalid Kaddoura, AECOM Mr. Alain Lalonde, Echologics Mr. Rabia Mady, Cima+ (Presenter)
As any infrastructure component, watermains are prone to deterioration due to ageing and other influencing factors. Although periodic inspections and renewals are needed, many municipalities confront difficulties in preserving all deteriorated assets due to budget constraints. The use of proper and cost-effective condition assessment, part of asset management, methodologies will enhance the allocation of budgets toward sustainable systems.
This paper developed a desktop analysis scheme that is applicable to buried Ductile Iron (DI) watermains to understand the existing condition of watermains. Similar to the Cast Iron watermain approach developed by Rajani & Markar (2000),the methodology relied on calculating the residual factor of safety (FoS) that would enable decision-makers in understanding the current structural conditions of the water linear assets based on field measurements. As part of the study, a Non-Distractive acoustic inspection tool was used to inspect seven kilometers DI watermains to provide information about the average remaining wall thickness of each pipe segment within the seven kilometers of DI pipe segmens. Â A comparison approach between the FoS approach and the inspection result were established to understand the difference between the two approaches pipe classification and/or condition grading. After categorizing the FoS outputs into three categories using the K-means clustering and establishing a confusion matrix for Good, Moderate, and Poor, the average accuracy was 81%. Besides, the study established a sensitivity analysis and considered the wall loss categorization of municipalities in Quebec by varying the wall thickness with a variety of operating pressures in the calculation of the residual FoS. As this study assesses existing conditions of watermains, decision-makers are able to prioritize and allocate municipal budgets to avoid catastrophic failure of linear assets
BIM and Lean for project planning and control
Ivanka Iordanova, Fernando Valdivieso, Carolyne Filion
Dr. Ivanka Iordanova, ETS - Pomerleau (Presenter) Mr. Fernando Valdivieso, ETS Ms. Carolyne Filion, Pomerleau
The productivity in the AECO industry is known to lag behind in growth compared to the other industries during the last several decades. Often featured as a conservative environment resistant to change, construction had not taken advantage from digital technology till very recently. This is about to change thanks to the adoption of BIM which seems to serve as an enabler. Literature suggests that improved preconstruction planning and scheduling are one of the ways to improve productivity.
This case study demonstrates that combining two powerful strategies (Lean and BIM) and working in collaboration with all project stakeholders leads to an efficient integrated construction process at a large Canadian GC company. The synergy between Lean Construction and BIM results in improved communication and better productivity of teams.
Three years ago, the company performed a comparative study on Lean Construction-based planning software (vPlanner, TouchPlan, BIM360 Plan, LeanKit) and the conclusion was that they either do not fit the construction project needs, or are not user-friendly enough to be implemented in a real job-site context.
The Innovation team, together with leading superintendents from the company, joined experience and forces towards an in-house developed solution. Based on Lean strategies and tools, it automates the links between widely used planning software, BIM models and job-site data, to create a platform with user-friendly access for all participant stakeholders. Using three loops of planning, scheduling and control, it connects relevant data between the Master Schedule, CPM, Takt Plan, the BIM model, and the visual communication documents (2D sheets, Virtual Reality).
The platform is used on a pilot project, which will be presented as a case study. Results from surveys with the project stakeholders will be discussed. They demonstrate that LEAN techniques combined with BIM models catalyse each other and that engaging the subtrades in the process is crucial.
The study will present:
Limitations of the platform, as well as future developments will be discussed.
Durability Assessment using Integrated Quality Management Framework in P3 Infrastructure Projects
Venkata Vemana, Smitha Koduru, Chris Gentile
Mr. Venkata Vemana, TransEd Partners Dr. Smitha Koduru, Veracity Engineering & Risk Consulting Services Mr. Chris Gentile, City of Edmonton (Presenter)
In Public-Private-Partnership (P3) infrastructure projects, the financial and service-life success of the project depends on the anticipated performance of infrastructure over its life-cycle. The life-cycle performance of P3 infrastructure projects is measured in terms of reduced repair and maintenance costs, as well as short duration of down-time due to the maintenance activities. Therefore, the durability of the infrastructure elements becomes an important component of the P3 projects.
During the construction stage, occurrence of deficiencies is an expected part of the projects. Remedial actions for the construction deficiencies often focus on meeting the design intent while reducing the impacts to the construction costs and schedule. As the infrastructure elements are designed according to the current codes and standards, meeting the design intent would address the safety and serviceability requirements of the infrastructure elements as defined in those standards. However, the requirements for durability over the infrastructure life-cycle are not explicitly considered in the current design codes and standards. Therefore, the planning and execution of P3 infrastructure projects requires additional contractual and construction quality management aspects to assess the durability requirements.
Development of the construction quality management aspects that address the durability of the remedial actions due to a construction deficiency is not an easy task. While the life-cycle performance of the infrastructure elements, as designed, can be estimated based on the existing infrastructure, there is no research in to the life-cycle durability performance of the remedial actions. Furthermore, as the remedial actions often involve the use of latest repair products and procedures, it adds to the difficulty in predicting the durability of the repaired component. In practice, not all construction deficiencies may result in the reduction of life-cycle durability. On the other hand, routine remediation actions may have significant impacts on the component durability.
In this paper, we propose an Integrated Quality Management Framework to address the durability issues due to the remedial actions following the construction deficiencies. The approach depends on identifying and categorizing the construction deficiencies that have no impact, moderate and significant impact on the durability. Categorization of the remedial actions on this basis would inform the consideration of warranty, maintenance costs, and risk transfer associated with each construction deficiency. This would improve the ability to manage the infrastructure durability either through the selection of alternative remedial actions or design changes to avoid such construction deficiencies.
IMPLEMENTING ONTARIO ASSET MANAGEMENT REGULATIONS AT CITY OF LONDON: A PRAGMATIC APPROACH
Khaled Shahata, Ahmed Eweda
Dr. Khaled Shahata, City of London Dr. Ahmed Eweda, City of London (Presenter)
Province of Ontario passed an asset management planning regulation under the Infrastructure for Jobs and Prosperity Act in December 2017 (588/17) and came into force January 2018. City of London developed an action plan and a schedule in order to comply with the regulations and its own internal deadlines and commitments. The implementation process faced some challenges; the major ones are highlighted in this paper. Moreover, lessons learned were presented.
SETON RECREATION FACILITY: A STEEL EFFORT FOR GREAT RESULTS
Maxime S Harvey
Located in Southeast Calgary (AB, CAN)) the brand-new SETON RECREATION FACILITY) is a multi-purpose building. There are both cultural and sporting amenities in it so everyone can benefit from this Calgary facility. The building includes: a competition pool, diving, waterpark, spectator viewing area, leisure pool, hot tubs/steam room, 2 multi-purpose ice rinks, 3 gymnasiums, fitness center, aerobic studios, 200m meters running/walking track, large and small rooms (for studios, classrooms and meeting spaces), full service library, youth center, art making, studio, gallery space, 250 seat theatre, childcare/child minding, food services and physiotherapy/medical clinic.Â
WHY IS STEEL CERTIFICATION ESSENTIAL? WHY SHOULD IT BE CONSIDERED MANDATORY?
In a world of global supply chains, all levels of government are facing new procurement and construction challenges. As with many pre-fabricated products, steel bridge girders could come from anywhere in the world. It can no longer be assumed that a fabricator will be familiar with Canadian bridge construction standards or have the facility, personnel and equipment capable of compliance with the contract requirements. It can also no longer be assumed that a fabricator will be concerned with his long-term reputation. The competitive bidding process can put price above all other considerations and owners have diminishing control over the enforcement of quality standards. The potential for compromising safety and durability have increased proportionately. To comply with the intent and requirements of CHBDC, The National Building Code and the Handbook of Steel Construction the engagement of a certified fabricator is an underlying guarantee of the expected work quality.
Some of the critical issues faced in bridge projects have common concerns which can be greatly mitigated with the adoption of steel bridge certification:
Defects and deficiencies;
Non-conformities to Codes and Standards;
Require intense inspection and testing;
Local fabricators consulted to solve and remedy issues;
To guarantee the best overall return of $ value for the public infrastructure projects and to ensure compliancy with the requirements of CHBD the adoption of steel bridge certification is essential.
Innovation and Information Technology in Civil Engineering
Fatigue Life Evaluation of the Diefenbaker Bridge Using Structural Health Monitoring
Christopher Morgan, Leon Wegner, Bruce Sparling
Mr. Christopher Morgan, WSP Canada Inc. (Presenter) Dr. Leon Wegner, University of Saskatchewan Dr. Bruce Sparling, University of Saskatchewan
As bridge infrastructure continues to age, public agencies must reliably determine which structures can remain in service, and which structures require rehabilitation or replacement. Structural fatigue is a common problem for many aging steel structures and its evaluation is one that carries a high level of uncertainty. Structural health monitoring is one technique that infrastructure owners can employ to reduce this uncertainty, thereby allowing them to make the necessary investment with confidence.
Structural fatigue occurs when steel components of a bridge are subjected to stress cycles, with every detail able to withstand only a limited number of cycles. The challenge in determining the remaining fatigue life of a bridge is the uncertainty in historical stress cycles and in-situ structural behaviour. The Canadian Highway Bridge Design Code (CSA S6-14) does not address fatigue life evaluation directly, and therefore, creates an even larger challenge for engineers. Structural health monitoring is a technique that engineers and owners can use to reduce this uncertainty because it helps to reveal actual stress levels and cycle counts.
Structural health monitoring was used to inform the determination of the remaining fatigue life of the Diefenbaker Bridge. The Diefenbaker Bridge is located in Prince Albert, Saskatchewan, Canada. The 304 meter long, seven span bridge consists of two separate fracture critical superstructures, each comprising a cast-in-place concrete deck supported by two welded steel I beams. The separate superstructures share a cast-in-place concrete substructure. Given the age of this bridge, and its history of frequent rehabilitation, an understanding of the remaining fatigue life was of critical importance to its owner since asset management plans depended on the outcome.
To perform the evaluation, the structure was instrumented with strain gauges, accelerometers, and a weather station. Data was collected for one year, and was used to characterize in-situ bridge behaviour (i.e. lateral load distribution, degree of composite action, dynamic load influence, bearing restraint) and to evaluate the bridge’s remaining fatigue life. Lastly, various methods of fatigue life evaluation were compared including deterministic methods, probabilistic methods, and AASHTO’s method.
This research proved that costly improvements to the fatigue prone details were not required, and that under current conditions, fatigue would not govern the service life of the structure. In addition to this, unexpected composite action and dynamic load influence was found to exist on the bridge.
Multiple Damage Localization of Gravity Dam: Strain Energy Based Approach using Random Data
Saikat Bagchi, Timir Baran Roy, Ashutosh Bagchi
Mr. Saikat Bagchi, Concordia University (Presenter) Mr. Timir Baran Roy, Concordia University Dr. Ashutosh Bagchi, Concordia University, Canada
Continuous monitoring of large-concrete structures like Dam, using real-time information obtained using the health monitoring system, is necessary for the prognosis of any premature degradation of the structure. In this study, standard section of the Koyna dam, is modeled in 2D using the ABAQUS software. Material properties of the dam material are assumed to be linear and elastic. The first four modes of free vibration are extracted using linear perturbation technique. The model is first validated against the available results for Koyna Dam. As real-time vibration data is sparse for the structures like Dam due to its size and location, Gaussian White Noise is used for next step validation purpose, which in turn provides a robust numerical model applicable for damage detection. Damage is incorporated in the numerical model introducing a suitable change in the modulus of elasticity of the elements at a specific location. Damages at multiple locations are compared individually. Reflecting these damages Displacement Mode Shape (DMS) and Curvature Mode Shape (CMS) of the structure change. Strain Energy based Damage Index Method is another approach which takes into account the change in the flexural rigidity and corresponding change in the stored energy at each element. Modal dynamic parameters like Natural frequencies, Mode Shapes and Element Strain Energy (ESE) are compared between the pristine and a hypothetically damaged state to comprehend the efficiency of the localization method. Studying the modal responses of the numerical model of the gravity dam it is inferred that the change in the natural frequency may not be a clear indicator of damage if the size of the damage is small in comparison to the overall size of the structure. It is observed that although DMS and CMS are able to approximately identify the region of the stiffness change, none of them is precise enough to localize the damaged elements. While on the other hand, the 1st and the 3rd modes of ESE can identify the damaged location with sufficient exactitude. Therefore, it is rational to hold that for the mass concrete structure like gravity dam strain energy is a better parameter for damage localization. Finally, in this study Strain Energy based damage index is estimated to quantify the extent of the damage.
NUMERICAL STUDY COMPARING ESTIMATED MANNING’S COEFFICIENTS USING THE DIRECT STEP METHOD
Nadia Hajjout, Mahdi Tew-Fik
Mrs. Nadia Hajjout, École Polytechnique de Montréal (Presenter) Dr. Mahdi Tew-Fik, École Polytechnique de Montréal, Département des génies civil, géologique et des mines (CGM)
Two numerical experiments were conducted, the first one involving a straight prismatic channel to simulate the unidimensional flow and the second experiment uses a curved rectangular channel to emphasize the 2D flow characteristics. The flow in both cases is modeled using a 2D model, SRH-2D, using given roughness parameters, Manning’s coefficients. Afterwards, the results of both numerical experiments are used to recalculate Manning’s coefficients, in each case study, by the direct step method (Slope energy) using the channel's centerline for the calculations. The aim of this paper is to compare the estimated Manning’s coefficients, for a prismatic and rectangular channel, in the case where the flow is mainly unidimensional and when the 2D effects are more obvious. In general, a good agreement is observed between the original Manning’s coefficients and the estimated one in the straight configuration whereas the second configuration demonstrates a divergence between suggested and calculated Manning’s coefficients.
The New Champlain Bridge’s expansion joints and SHM system – Supply, installation, implementation
Alexis Lauzon, Borja Baillés, Gianni Moor, Mark Treacy, Andrea Paciacconi
Mr. Alexis Lauzon, Mageba (Presenter) Mr. Borja Baillés, Mageba Mr. Gianni Moor, Mageba Mr. Mark Treacy, Mageba Mr. Andrea Paciacconi, Mageba
The New Champlain Bridge, currently being constructed in Montreal, Quebec, has a total length of 3,400 m – mostly short spans, but also including a cable-stayed structure with a main span of length 240 m. This paper shall relate to two specific aspects of the bridge’s construction – the modular expansion joints that will enable the bridge’s superstructure to optimally accommodate movements and rotations, and the extensive structural health monitoring (SHM) system that will efficiently and automatically provide detailed, precise information on many key factors relating to the bridge’s condition and performance and thus support bridge inspection and maintenance work. With construction of the bridge approaching completion at the time of writing this abstract, these key technological features are currently being installed. The paper shall describe the supply and installation / implementation phase of the expansion joints and the SHM system, highlighting the benefits of their use to the bridge owner and operator over the coming decades.
The Value of Structural Health Monitoring of a Corroded Reinforced Concrete Beam
Mao Xiaoyi, Leon Wegner
Ms. Mao Xiaoyi, University of Saskatchewan (Presenter) Dr. Leon Wegner, University of Saskatchewan
Corrosion is a major factor that causes degradation of reinforced concrete structural elements, especially in cold regions where de-icing salts are used extensively. It is difficult to assess the remaining capacity of a corroded reinforced concrete member based on visual inspections alone, and therefore to determine whether the member has an adequate level of safety. Structural health monitoring (SHM) can provide real-time information about a structure’s actual condition, thereby mitigating the risk of failure if the structural condition is worse than presumed, or extending the service life and saving the replacement costs if it has an adequate level of safety.
This paper describes the results of a laboratory-based experimental study undertaken to evaluate the effectiveness of an SHM technique for determining the bending moment capacity of a corroded reinforced concrete beam and its remaining level of safety in terms of the reliability index. The SHM technique is designed to estimate the remaining effective cross-sectional area of the reinforcing bars after corrosion, which can then be used to predict the remaining structural capacity and service life, as well as the degree of certainty associated with these predictions. Three batches of reinforced concrete beams were subjected to different levels of accelerated corrosion before being tested under service load levels while gathering data using several different types and combinations of instrumentation. The accuracy of each beam’s capacity estimate will be determined based on the measured failure load. In addition, the reliability index associated with each combination of instrumentation and level of corrosion will be calculated. Finally, a life-cycle cost analysis for each beam and monitoring system will be performed, based on a target reliability index, and the value of implementing SHM systems will be discussed.
The preliminary results of this study show that the SHM technique can predict the remaining effective area within 10% error. Also, with the additional information provided by the SHM systems, the uncertainty of the structural capacity decreased, the structural reliability increased, and the maintenance and replacement cycles of the structure could be optimized. Therefore, this topic will be of interest to infrastructure owners and inspectors, and, due to the popularity of public-private partnership (PPP) projects across Canada in recent years, structural designers and contractors may also have interest in this topic.
Innovation and Information Technology in Civil Engineering
Comparison of lift path finding algorithms for mobile crane in congested site
Serim Park, SangHyeok Han
Mrs. Serim Park (Presenter) Dr. SangHyeok Han
In heavy industrial projects, modular based construction is getting popular because of its efficiency and the lower cost. The key success factor of modular industrial projects is lift path planning that influences the productivity and safety through the entire process. Many algorithms such as hill climbing, A *, and genetic algorithms are introduced by researchers for mobile crane lift path planning. However, a comprehensive comparison of these algorithms is not done yet to identify the direction of potential research for the mobile crane lift path. This paper compares the algorithms for the lift path planning of mobile crane in the modular-based heavy industrial project to find the competent method to search the collision-free path with the lower operating cost and less computation time. The lift path planning for the mobile crane is currently in progress with two algorithms in this paper: A* search and Genetic algorithm. In the algorithms, the crane configuration (combination of swing, luffing, and hoisting) is defined to move the modules from pick location to the final location. The algorithms are developed in Python and Matplotlib is used for the visualization. The results of these will be compared with two other algorithms that already developed by Alberta University. The case study is based on the industrial modular project by PCL industrial Management in Alberta, Canada, that includes a considerable number of module liftings by mobile crane (Demag CC 2800). The sample modules to analyze are selected by its difficulty of work (levels of congested site areas) which are classified by three levels based on the scheduled sequence, obstacles, and the installation level. The algorithmsâ€™ results are compared by criteria such as computation time, the number of movements, success rate, the linear travelling distance of module, and crane operation time to determine the effectiveness for the path planning of mobile crane in the heavy industrial projects. This comparison will show us which algorithm is more effective for the crane path planning in heavy industrial projects and suggest the direction of further research.
Automated Data Management At Scale â€“ Flexible Platform for Data Integration and Geohazard Analysis
Suchismitha Vedala, Rayhaneh Azarm
Ms. Suchismitha Vedala Ms. Rayhaneh Azarm, Canary Systems Canada Inc. (Presenter)
Implementation of a complete and dynamic data management system for handling all the types of geotechnical instrumentation for large project is a challenging task. Canary Systems manages data for projects with thousands of concurrent instruments. The types and quantities of data that are available to help clients understand their operational and safety risks have increased tremendously in recent years.
Technology advancements have introduced many new types of data beyond traditional geotechnical instrumentation, such as automated total stations, TDR, differential GPS, ground-based radar, satellite InSAR, laser scanners, vibration/seismic recorders, environmental sensors such as rainfall or air quality, among others. While the collection of these data is no longer a technical challenge, the danger presented is the integration and management of all the different sources of data into a single reliable system that can not only store the data but also provide flexible visualization and reporting.
Canary System’s web-based software allows infrastructure, dam safety and mining industries to import data from various sources and dynamically update all the related charts and reports. The system supports any number of users to be connected simultaneously, allowing clients and external consultants to work together in a single platform and ensure the project safety in unprecedented fashion. The system can be programmed to immediately inform users of data consistency issues and can flag any data that is outside of the expected ranges, either indicating that maintenance might be necessary, or to inform of geotechnical safety considerations. Detailed and complex custom reports can be produced for each site, where data is carefully reviewed and correlated with the other instrument readings or activities in the area to provide a high level of confidence in the geotechnical performance.
On developing proper single and ensemble machine learning frameworks for predicting seismic-based soil liquefaction
Mohammad Alobaidi, Mohamed Meguid, Fateh Chebana
Dr. Mohammad Alobaidi, McGill University (Presenter) Dr. Mohamed Meguid, McGill University Dr. Fateh Chebana, Eau Terre Environnement, Institut National de la Recherche Scientifique
Seismic-induced liquefaction of soils is one of the major ground failure consequences of earthquakes. This phenomenon leads to catastrophic loss of lives and irreversible damage to the critical infrastructure. Prediction of liquefaction potential is, hence, considered as the major research frontier in geotechnical earthquake engineering. Conventional techniques used to determine the level of liquefaction susceptibility of soil mainly relied on informed-determination of liquefaction threshold from observed soil behavior records against key-parameters such as Standard Penetration Test and Shear Wave Velocity. Statistical procedures were also commonly utilized in producing useful inferences about the likelihood of liquefaction given some soil-related as well as earthquake-related information. Nevertheless, with the ever-lasting need of more robust techniques that can provide better generalization ability over a wide collection of liquefaction observations from different databases, rather than local thresholding of the phenomenon, more complex methods are required. The availability of computational recourse nowadays further motivated the creation of more complex techniques that have provider far better performance than their predecessor. Recently, evolutionary Machine Learning techniques have been proposed in the broad literature and provided superior performance in learning complex relationships, while maintaining a reliable generalization ability. A more recent advancement in Machine Learning is Ensemble Learning. This new framework is generally defined as the generation-learning-fusion of individual Machine Learning models in a predefined ensemble architecture that not only produces a far stable global model, but also guarantees higher performance and diminishing uncertainty. To this extent, in liquefaction prediction studies, limited adherence to proper utilization of Machine Learning have been observed over the considered literature. Also, little attention has been paid to the recent development in supervised learning techniques and exploiting them toward enhanced liquefaction prediction. This work presents different Ensemble Learning frameworks and examines their capability in enhancing liquefaction prediction. Different Machine Learning techniques in Ensemble Learning frameworks are investigated over a seismic-based liquefaction database. The performance of the resulted models is compared with single models used in the literature, and the effect of the training data-availability on the ensemble modelsâ€™ generalization ability is also examined.
Keywords: Machine learning; ensemble learning; classification; liquefaction prediction.
Research on Uniformity Detection Method of Asphalt Mixture during Paving Process Based on Digital Image Technology
Wei Yu, Naixing Liang, Susan Tighe
Dr. Wei Yu, university of waterloo (Presenter) Dr. Naixing Liang Dr. Susan Tighe, CPATT - University of Waterloo
Focus on the problem of continuous real-time monitoring of aggregate distribution uniformity during asphalt pavement paving process, an asphalt mixture separation and identification method based on image processing technology and a uniformity evaluation method based on static moment theory were proposed. Firstly, the colour photos shot from 60cm high was preprocessed by graying, filtering and equalization to get the high contrast and low noise gray image. And then, using the image threshold segmentation method and morphological image processing to separate the aggregate and gain the binary image. In this process, we develop the watershed segmentation method with the Extended-Maxima transform, which can significantly eliminate the over-segmentation of the image, and achieve fast and accurate segmentation of the adhesion particles. Considering the influence of aggregate size and distribution position on the uniformity, the product of aggregate particle area and distance to image boundary is used as the basis for uniformity evaluation. The concept of uniformity is proposed, and then the boundary criteria were determined by analyzing 1,000 random on-site collected paving photos. When the uniformity is less than 0.91, the aggregate is in the uneven state, and vice versa. Moreover, the remaining 85 photos verified the accuracy of the demarcation criteria. The example and validation test indicate that the uniformity analysis method may be efficiently applied to the evaluation of aggregate distribution on asphalt mixture during the paving process.
Innovative and Emerging Materials
Abrasion resistance of high performance specified density concrete
Ali Abdel-Hafez, Amgad Hussein, Stephen Bruneau
Mr. Ali Abdel-Hafez, Memorial university of newfoundland (Presenter) Dr. Amgad Hussein, Memorial University of Newfoundland Dr. Stephen Bruneau, Memorial University of Newfoundland
The current study was conducted to evaluate the effect of different nano materials on the performance of high performance modified normal density concrete (HPMNDC) with 50% replacement of coarse aggregate by lightweight aggregate. The study was targeted to providing enhancement to the mechanical properties and abrasion resistance of the HPMNDC by using advanced materials and optimizing the mixture proportions. For this purpose, two types of Nano-materials, colloidal silica (CS) and titanium dioxide (TD) were used in nine different concrete mixtures. The ratios of cement replacement with CS were 1%, 3%, 5%, and 7%. For the TD, the replacement ratios were 0.6%, 0.8%, 1%, and 1.2%. The mixtures were made with 550 kg/m3 of cement and 0.30 water to binder ratio. The mixtures also included the usage of metakaolin (MK) and fly ash (FA) as partial cement replacement materials, both at 10%, along with inclusion of basalt fibers (BF) at 0.1%. The concrete specimen were tested using destructive and non-destructive methods to evaluate their performance. The tests results revealed that, the incorporation of both types of materials, led to some enhancement of the HPMNDC abrasion resistance and mechanical properties. The preliminary results indicated that the optimum content of CS in the HPMNDC mixtures turned to be 3%, while the TD optimum content was 1%. Also, the study provides some empirical relationships between abrasion resistance and different test parameters. The experimental results and the proposed equations were in reasonable agreement.
Compressive Strength of Hemp-Substituted Concrete
Michelle Liu, Colin Van Niejenhuis, Roberto Aurilio, Hassan Baaj
Ms. Michelle Liu, CPATT - University of Waterloo (Presenter) Mr. Colin Van Niejenhuis, University of Waterloo Mr. Roberto Aurilio, CPATT - University of Waterloo Dr. Hassan Baaj, University of Waterloo
Hemp is an organic material particularly well known for its industrial applications. It is a species of the cannabis family and has historically been stigmatized due to its resemblance and genetic proximity to marijuana. With the recent legalization of marijuana in Canada, the interest in hemp may become widespread in the building industry upon overcoming its supply barrier. Hemp possesses various beneficial properties as a building material, including its renewable nature and ability to sequester carbon throughout its cultivation and service life. This paper aims to explore the use of hemp as a partial substitution for aggregates in regular concrete mixes for non-structural uses, with the resulting compressive strength being of primary interest. Concrete cylinders with 10%, 15% and 20% hemp shivs by volume were created and subjected to standard laboratory compressive strength test after 28 days. Compressive strength and dead load are expected to be inversely related to hemp content, and insulation properties are expected to be directly proportional to hemp content.
EFFECT OF PCMS ON MECHANICAL PROPERTIES OF HEAT CURED MORTAR
Mohammad Al-Shdaifat, Ahmed Soliman
Mr. Mohammad Al-Shdaifat, Concordia University (Presenter) Dr. Ahmed Soliman, Concordia University
Using phase change materials (PCMs) in cement mixtures has become an interesting area of research in the recent decade. PCMs have that abilities to enhance cement mixtures properties like thermal capacity and thermal resistance. In this study, microencapsulated PCMs were incorporated in mortar mixtures at a rate of 3%, 6%, and 12% as a replacement of sand at exposed to a standard heat curing profile. Fresh and mechanical properties including flow table, setting time, heat of hydration, compressive and tensile strengths, were evaluated for all mixtures. Moreover, representative samples from optimal mixtures were examined using differential scanning calorimetry (DSC), scanning electron microscope (SEM) and X-ray diffraction (XRD). Results indicated that the addition of PCMs will affect the development for different tested mixtures. The higher the added dosage, the great the effect.
Key Words: phase change materials, mortar, Compressive Strength
EFFECTS OF ACTIVATOR PROPERTIES ON IMPACT BEHAVIOUR OF ALKALI ACTIVATED SLAG MORTAR
Ahmed Abubakr, Ahmed Soliman, Sameh Hassan
Mr. Ahmed Abubakr (Presenter) Dr. Ahmed Soliman, Concordia University Mr. Sameh Hassan, Concordia University
Alkali activated systems are considered the third generation of binding systems. Alkali Activated systems are characterized by low carbon dioxide emission and superior mechanical and durability performance compared to cement-based systems. This study will focus on characterizing the performance of alkali activated slag (AAS) mortar under impact loads. Sodium hydroxide and sodium silicate were combined to form the activator for all tested mixtures. Effects of activator dosage and properties including sodium oxide (Na2O%) and silicate modulus (Ms) on strength and Impact resistance of AAS mortar were evaluated. Results showed that impact resistance was enhanced as the Na2O% increased up to 8 % which is similar to the improvement in compressive strength. Moreover, at the same Na2O%, increasing Ms up to 2 was found to improve the impact resistance. There was a relationship strength and impact resistance improvements.
Keywords: alkali activated slag, mechanical properties, impact.
Grout For Two-Stage Alkali Activated Concrete
nada zod, Ahmed Soliman
Mrs. nada zod Dr. Ahmed Soliman, Concordia University (Presenter)
Production of ordinary Portland cement (OPC) has several negative ecological and environmental impacts. This includes rapid depletion of natural sources and high carbon dioxide (CO2) emissions. Many attempts have been made to find an alternative binder for OPC. Among differently proposed binders, alkali-activated material (AAM) showed promising performance. It is characterized by very low carbon footprint along with low strain on natural resources as it mainly composes of industrial by-products. Therefore, this study investigates the potential of using AAM as a replacement for OPC in different construction applications, especially, two-stage concrete (TSC). Different grout mixtures using slag, as the main precursor, and various activator types and concentrations were prepared. Fresh and hardened properties, including efflux time, setting time and compressive strength, were evaluated for all grout mixtures to ensure fulfilling the requirements for TSC productions. Results confirm the high potential for producing green sustainable TSC using alkali-activated slag grouts. A linear relationship between the compressive strength for grout and TSC was found similar to the conventional OPC TSC. It is anticipated that the finding of this study will pave the way for wider implementation of AAM in different construction applications.Â
Key Words: Alkali-Activated Materials, Two-Stage Concrete, Efflux Time, Grout, Compressive Strength
SOUND INSULATION SYSTEMS FOR RESIDENTIAL BUILDINGS
Ali ElSaeed, George Naguib, Ahmed El-Mekawy, Athnasious Ghaly, Moustafa El Assaly, Reem Abou Ali, Mohamed N. Abou-Zeid
Mr. Ali ElSaeed, The American University in Cairo (Presenter) Mr. George Naguib Mr. Ahmed El-Mekawy Mr. Athnasious Ghaly, American University in Cairo Mr. Moustafa El Assaly, Mr Ms. Reem Abou Ali Dr. Mohamed N. Abou-Zeid, The American University in Cairo
Acoustic noise can be a major source of pollution particularly in densed residential areas. A research conducted in a busy neighborhood in Cairo, Egypt concluded that street noise exceeded the permissible limits at three different times of the day. Hence, the introduction of sound insulation materials to residential areas, among others, can help reduce noise without completely muting the exterior noise to maintain a level of awareness of the surrounding environment. The main purpose of this study is to help assess various means of sound insulation systems in structures at different levels of sound frequency intervals. Three different types of materials; natural cork, rockwool and blue foam, were investigated for their performance as sound insulating materials, along with their thermal insulation property. For the purpose of this investigation, a special control room was constructed using conventional cement bricks with conventional plastering mortar. A partition wall was built in the middle of the room to divide it into a source room and a receiving room. The insulation materials were installed on the partition wall. The acoustic insulation behavior was tested by setting monotone sounds at the same amplitude at various frequency intervals covering the human hearing range. The results demonstrated that each material had different acoustic insulation behavior under the various levels of sound frequencies tested. In general, cork has yielded the best sound insulating results while having the lowest conductivity. Recommendations are made as to how to improve sound insulation in residential buildings.
The Effects of Superabsorbent Polymer (SAP) on Concrete in Marine Environment
Opeyemi Joshua, Olatokunbo Ofuyatan, Ayobami Busari, Isaac Akinwumi, David O. Nduka, Ayodele O. Ibitayo, Olayinka Oloke
Dr. Opeyemi Joshua, Department of Building Technology, Covenant University. Nigeria (Presenter) Dr. Olatokunbo Ofuyatan, Covenant University Dr. Ayobami Busari, Covenant University Dr. Isaac Akinwumi, Department of Civil Engineering, Covenant University, Ota, Nigeria Mr. David O. Nduka, Department of Building Technology, Covenant University, Nigeria. Mr. Ayodele O. Ibitayo, Department of Building Technology, Covenant University, Nigeria. Dr. Olayinka Oloke, Department of Estate Management, College of Science and Technology, Covenant University,
The quest for high strength concrete (HSC) has given rise to the use of several blends/additives with cement like silica fumes, fly ash and granulated blast furnace slag. The major technique employed to achieve HSC is lower water/cement (w/c) ratio. One major additive used to achieve very low w/c ratio is the superabsorbent polymer (SAP) with superplasticizers. SAP which is applicable in HSC can hold water in concrete and gradually release it for curing for optimal strength development where external curing water cannot easily access. The very high water absorbent property of SAP is the desired characteristics in HSC applications, but when it is exposed to sodium chloride (NaCl) salt, it rapidly losses its absorbent property and hence, the ability to improve strength in concrete. The major solute in marine water is NaCl at varying concentrations. This study aims to assess the effects of the NaCl in the marine environment on the SAP within the concrete and its effect on the concrete strength. Normal-strength class concrete was used in this study and cured in marine water, this is to allow for better curing-water (with dissolved NaCl) ingress into the concrete to magnify the effect. Concrete mix-design to attain a target strength of 30MPa was mixed and cast into 100mm cube mold. The control was cast and cured in fresh and marine water, the test concrete cubes were mixed with SAP and cured in marine and fresh water. Superplasticizers were used in all the mixes. Result shows that concrete cast with SAP required more water for good workability but the ones cured in the marine water had significant reduced strength than the ones cured in fresh water. More significant strength difference was observed with the SAP concrete cubes cured in fresh and marine waters. This study concludes that there is a significant interaction between the SAP and the marine water. It is recommended that microstructural studies be performed to study the salt-SAP interaction that resulted in reduced strength.
Life Cycle Analysis & Costing
A FRAMEWORK FOR PAVEMENT TREATMENT ALTERNATIVE SELECTION THROUGH LIFE CYCLE COST ANALYSIS
Song He, Ossama Salem, Baris Salman
Dr. Song He, George Mason University Dr. Ossama Salem, George Mason University (Presenter) Mr. Baris Salman, Syracuse University
Aging road infrastructure and budgetary limitations have made it increasingly important to optimize roadway maintenance, repair, and rehabilitation (MRR) expenditures in the United States. For the past few decades, several non-traditional rehabilitation techniques, such as the use of warm mix asphalt, cold in-place recycling, full depth reclamation, and intelligent compaction, have proved effective in addressing asphalt pavement deficiencies while reducing project costs, shortening activity durations, and improving quality of work. While many studies have been conducted on the life cycle costs of MRR projects, very few have evaluated non-traditional techniques with in-depth analysis of user costs. This study focuses on life cycle cost analysis (LCCA) of these non-traditional techniques by investigating agency costs, user cost due to travel delay, user cost due to additional fuel consumption, and user cost due to higher numbers of crashes. A total of six life cycle MRR alternatives were developed, where four represent the non-traditional techniques and the other two represent traditional techniques as benchmarks. Cost data for agency costs were obtained through a survey of state departments of transportation and RSMeans 2016. User cost data were obtained from literature, within which fuel consumption costs were estimated through Motor Vehicle Emission Simulator. Results show that alternatives involving asphalt recycling and intelligent compaction have lower overall life cycle costs. It is also concluded that user travel delay costs account for a major portion of the overall life cycle costs, so decision makers are recommended to select MRR techniques with minimum disruption to commuters’ mobility.
Conceptual Cost Models for Early Energy Simulation in Building Projects
Leila Rafati Sokhangoo, Rafaela Panizza, Mazdak Nik-Bakht, SangHyeok Han
Ms. Leila Rafati Sokhangoo, Concordia University (Presenter) Ms. Rafaela Panizza, Concordia University Dr. Mazdak Nik-Bakht, Concordia University Dr. SangHyeok Han
Economic analysis has been known as one of the major challenges for energy consultants in early phases of design, when project characteristics are not clear enough. One source of the challenge is to obtain cost data for elements based on their energy performance (rather than the product information). Therefore, quantitative economic analyses are usually postponed to later phases, when changing the decisions (which are already made) is costly and challenging. In response to this need, the present study aims to develop conceptual cost estimation models which can be used by energy simulation tools in early phases of projects (i.e. Schematic Design). These parametric cost models can assist energy simulator engines to estimate installation costs of building elements, based on parameters indicating their energy efficiency performance. In this study, three main categories of design parameters which significantly influence building energy consumption were considered: envelope (walls/roof insulation and windows/fenestration); lighting systems; and heating, ventilation and air conditioning (HVAC). For each component, cost databases such as RSMeans, and other commercial vendor databases were used for analysis based on physical parameters governing the energy performance of each element. Those parameters include R-value for insulation; U-Value and Solar Heat Gain Coefficient (SHGC) for windows; Lighting Power Density (LPD) for lighting; and efficiency for HVAC systems. To assist in recording and updating values for the cost model, a database was developed based on building energy performance parameters. The database is used in a life cycle cost analysis software and integrates well with Building Information Modeling (BIM), which can help energy consultants to start quantitative life cycle cost analyses during early design phase.
Fall Prevention Supplementary Devices for Bridge Construction Workers: A Life Cycle Cost Analysis
Ahmed Al-bayati, Aslihan Karatas, Jeanette White
Dr. Ahmed Al-bayati, Western Carolina University (Presenter) Dr. Aslihan Karatas, Lawrence Technological University Mrs. Jeanette White, Southwestern Community College
Construction workers along bridge decks or overpasses have experienced a substantial number of fatal and non-fatal injuries in the United States. An investigation of fall prevention along the bridge decks reveals the existing guardrail barriers do not meet the required height that needed to provide adequate fall protection for construction workers. Therefore, fall protection supplementary devices (FPSDs) must be temporarily or permanently installed to prevent fall injuries. There are several options of FPSDs that could be installed by construction crews. The current study conducts a life cycle cost analysis (LCCA) of two FPSDs options that could be utilized to extend the existing guardrails’ barrier height. The two options are (1) installing temporary barrier protection along the existing guardrails to increase the barrier height to an acceptable level, and (2) Installing fixed anchor points or sliding rail connections along the bridge deck guardrail. As for the first option, the Bodyguard Rail - clamp CC120 and the Master Clamp MCC130 have been identified as being most compatible with over 80% of all existing bridge deck guardrail barriers which are the concrete New Jersey Barrier Rail, and the Aluminum 1-Bar Metal Guardrail. On the other hand, the second option requires construction workers to use full-bodied harnesses and connect to the permanently installed anchor point or sliding rail. Accordingly, both options of fall protection have been compared on a similar basis to adequately compare the life cycle cost (LCC). The two options were equated to a total cost per 100 linear feet (LF) of installation, and both options were assumed to be installed over a full year of need. Therefore, all associated costs were included in the estimation such as material costs, competent person installation/labor cost, and yearly inspection and repair costs. Accordingly, the LCCA reveals the fixed anchor as the most economical choice. Although the fixed anchor has a higher initial annual cost, this option has a minimal repetitive annual cost. Finally, further investigation should be conducted to compare the compatibility of the suggested options with the practices and conditions of the workplace.
Identifying Manageable Scope Creep Indicators and Selecting Best Practice Strategies for Construction Projects
Sharareh Kermanshachi, Elnaz Safapour
Dr. Sharareh Kermanshachi, University of Texas at Arlington (Presenter) Mrs. Elnaz Safapour, University of Texas at Arlington
Many construction projects suffer from changes to the scope of the project during the construction phase. Because the changes ultimately lead to substantial cost overruns and major scheduling delays, scholars and practitioners worldwide are assessing their impact and the critical causes behind them, but are finding it challenging to ameliorate or eliminate them with appropriate strategies. To mitigate the consequences of scope creep, it is beneficial to first identify the critical root causes so that appropriate strategies can later be implemented. The aim of this study is to identify the scope creep indicators (SCIs), then analyze and quantify the impacts of implementing best practices. For this purpose, a structured survey was developed and distributed to qualified professionals involved in construction projects. The research team collected 37 completed surveys, and used appropriate statistical data analysis to obtain the results. The results revealed that communication among owners, the number of oversight entities, and the projectâ€™s location are three important factors that lead to scope creep, and that alignment, partnering, front-end planning, material management, and dispute prevention are important to mitigating its cost. The outcomes of this study will assist project managers in identifying potential sources of scope creep early in their projects, and in applying appropriate BPs to minimize their impact throughout the execution of construction projects.
Life Cycle Cost Analysis of Light Steel Framed Buildings with Cement-Based Walls and Floors
Metwally Abu-Hamd, Mona Abouhamad
Dr. Metwally Abu-Hamd, Cairo University Dr. Mona Abouhamad, Cairo University (Presenter)
Light (cold-formed) steel framing systems (CFS) have proven to be an efficient alternative to traditional building construction systems in low and mid-rise residential and office buildings due to their high strength-to-weight ratio, ease and speed of construction and high recycled content. In order to evaluate their competitiveness over other construction systems, their life cycle cost must be assessed. The life cycle costs over the building life is widely acknowledged as a better indicator of the value for money than the initial construction costs alone. Most available studies on life cycle cost analysis focus on traditional construction material and systems such using timber, reinforced concrete and hot-rolled steel. There is an absence of detailed scientific research or case studies dealing with the potential environmental benefits of off-site construction, particularly the reduced environmental impact and the savings in embodied energy resulting from waste reduction and the improved efficiency of material usage.
The objective of this study is to perform a life cycle cost analysis of CFS buildings in which walls are sheathed with cement-based boards and floors have thin reinforced concrete slabs. This analysis is used to identify the cost proportion of each stage and also to compare life cycle cost of different building material and construction systems alternatives. Life cycle cost is evaluated as the present value of the total cost of the building and its energy consumption throughout its life; including the costs of planning, design, construction, operations, maintenance and disposal, less any residual value. The analysis is performed based on the methodologies outlined in ASTM E917 and ISO 15686-5 for life cycle costing. The study integrates the results of life cycle energy analysis with life cycle cost of construction, maintenance and end of life. Sensitivity analysis is conducted to identify how variability in the input values; e.g., fluctuations in material prices, affects the results. The developed methodology is applied to a university building constructed at Cairo University using the described structural system. The life cycle cost of the building is compared with the life cost of the same building if it was constructed using traditional hot-rolled steel or reinforced concrete and brick walls.
Materials and structure env load/Self-consolidating concrete
DEVELOPMENT OF SINGLE, BINARY AND TERNARY ALKALI-ACTIVATED SCC: MICROSTRUCTURE AND PERFORMANCE
Dima Kanaan, Ahmed Soliman
Ms. Dima Kanaan, Concordia University (Presenter) Dr. Ahmed Soliman, Concordia University
This study investigates the effect of single, binary and ternary combinations of slag, fly ash and silica fume precursor materials on workability and mechanical properties of various alkali-activated self-consolidating concrete (AASCC) mixtures. Fresh and mechanical properties including L-Box, inverted slump test, compressive and tensile strengths, and modulus of elasticity were evaluated for all mixtures. Moreover, representative samples from optimal mixtures were examined using differential scanning calorimetry (DSC), scanning electron microscope (SEM) and X-ray diffraction (XRD). Results indicated that AASCC can be produced with high-volume composite binders and achieved an acceptable fresh and hardened characteristics.
Keywords: Alkali-activated concrete, self-consolidating concrete, workability, SEM
EFFECT OF ACTIVATOR COMPOSITION ON THE PERFORMANCE OF ALKALI-ACTIVATED SCC
Dima Kanaan, Ahmed Soliman
Ms. Dima Kanaan, Concordia University (Presenter) Dr. Ahmed Soliman, Concordia University
This study investigates the influence of varying the concentration of sodium oxide (Na2O) and activator modulus (Ms) i.e. SiO2/Na2O on workability and mechanical properties of various alkali-activated self-consolidating concrete (AASCC) mixtures. Three Na2O dosage levels (i.e. 4%, 6% and 8%) in addition to SiO2/Na2O ratios (i.e. 1, 1.25 and 1.5) of the alkaline solutions were considered in the study. Fresh and mechanical properties including L-Box, inverted slump test, compressive and tensile strengths, and modulus of elasticity were evaluated for all mixtures. Moreover, representative samples from optimal mixtures were examined using differential scanning calorimetry (DSC), scanning electron microscope (SEM) and X-ray diffraction (XRD). Results indicated an increase in the mechanical properties was observed while increasing the Na2O concentration and Ms ratio, yet the workability decreased.
Keywords: Alkali-activated concrete, self-consolidating concrete, workability, SEM
Segregation Resistance of Self-Consolidating Concrete Incorporating Palm Oil Fuel Ash
Self-consolidating concrete (SCC) requires excellent filling ability and passing ability as well as adequate segregation resistance for successful applications. However, achieving the required segregation resistance for SCC is a challenging task. This study presents the segregation resistance of SCC incorporating palm oil fuel ash (POFA), which is an agro-waste generated in palm oil industry. Twenty SCC mixtures were produced based on the water to binder (W/B) ratios of 0.25-0.40 and incorporating POFA in the range of 0-30% by weight of cement. Sufficient dosage of high-range water reducer (HRWR) was used to achieve the required self-consolidation capacity for the concrete mixtures. The segregation resistance of the SCC mixtures was examined by sieve and column segregation tests. The segregation indices and segregation factors of the SCC mixtures were obtained from sieve and column segregation tests, respectively. In both tests, the effects of W/B ratio and POFA on the segregation resistance of SCC were observed. Test results revealed that the segregation index varied in the range of 9–18.9%. The lowest value of segregation index was obtained for the SCC produced with the W/B ratio of 0.40 and a POFA content of 0% and the highest value was achieved for the SCC prepared with the W/B ratio of 0.25 and a POFA content of 30%. On the other hand, the segregation factor varied in the range of 8–21.8%. The lowest segregation factor was found for the SCC mixture produced with the W/B ratio of 0.35 and 0% POFA content whereas the highest value was achieved for the SCC mixture made with the W/B ratio of 0.25 and 30% POFA content. Higher segregation index and segregation factor indicate a lower segregation resistance for SCC. The recommended maximum limit for segregation index is 18% and the acceptable maximum segregation factor is 20%. The overall test results showed that both W/B ratio and POFA content significantly affect the segregation resistance of SCC depending on the dosage of HRWR used in concrete mixture. However, all concretes passed the requirements of segregation resistance, except for the concrete mixture produced with the W/B ratio of 0.25 and 30% POFA content. On the whole, the research findings suggest that SCC can be produced successfully using POFA as a partial replacement of cement.
Using TDA to partially replace coarse aggregates in concrete mixtures
Abdelmoneim El Naggar, Pedram Sadeghian, Hany El Naggar
Mr. Abdelmoneim El Naggar, Dalhousie University (Presenter) Dr. Pedram Sadeghian, Dalhousie University Dr. Hany El Naggar, Dalhousie University
Applications utilizing rubberized concrete have grown substantially in the last decade as an answer for the scrape tires stockpiling problems and its associated environmental issues. Though rubberized concrete mixtures generally have a reduced compressive strength and stiffness that may limit their use in specific structural applications, they possess several desirable properties such as lower density, higher toughness, and better dampening ability resulting in an enhanced dynamic performance. The purpose of this study is to investigate the effect of using recycled Tire Derived Aggregates (TDA) to partially replace coarse aggregates in concrete mixtures. Natural coarse aggregates in the considered concrete mixtures was partially replaced by 10%, 20%, and 30% of TDA. The specimens were tested under uniaxial compression up to failure. The results showed a decrease in the compressive strength and the elastic modulus of the concrete as the replacement ratio increase. It was observed that increasing the content of TDA to 30% of the coarse aggregates by volume decreased the compressive strength and elastic modulus of the concrete by 36% and 12%, respectively. This is a research in progress and more results on higher content of TDA will be provided later.
Materials and structure env. load
A Comparison of Plain and Deformed Hooked Bars in Concrete
Bjorn Vors, Lisa Feldman
Mr. Bjorn Vors, University of Saskatchewan Dr. Lisa Feldman, University of Saskatchewan (Presenter)
Hooks are provided on reinforcing bars when the straight length between the bar and the point at which full development is required is insufficient to allow for the necessary force transfer with the surrounding concrete. Hooks, when properly detailed, therefore enhance bar development and minimize bar slip, and are even more critical for the plain (i.e. undeformed) bars that were used reinforcement in Canada until about the mid-1950s.
An experimental investigation is therefore underway at the University of Saskatchewan to assess the effectiveness of hooked plain bars, as compared to modern deformed bars, in exterior beam-column joint specimens. Both 90° and 180° hook geometries are being evaluated for both bar types. Hook capacity, bar slip, and observations of the resulting failure modes are being recorded for all specimens.
This paper presents the experimental design of the overall program and presents the findings of the initial phase of specimen testing.
Effect of High Strain-Rates in Heavy Timber Connections
Christian Viau, Ghasan Doudak
Mr. Christian Viau, University of Ottawa (Presenter) Dr. Ghasan Doudak, University of Ottawa
This paper reports on the experimental results from a research program investigating the blast performance of glued laminated timber columns and cross-laminated timber wall panels with and without realistic boundary conditions. Quasi-static and dynamic testing on components as well as full-scale specimens was conducted in order to quantify the effects of short-term duration loads. Dynamic testing was conducted through the use of a shock tube, a test apparatus capable of simulating far-field blast explosions. Reported in this paper are the qualitative and quantitative results from the experimental portion of the program. At both component and full-scale level, dynamic increase factors (DIFs) were measured for various tested connections. It was found that the current Canadian Blast Design Standard provisions for wood connections are inadequate for blast design. Recommendations are made based on the findings of the study.
Elastic buckling behaviour of ?-shaped rack columns with patterned holes under compression
Peng Zhang, Shahria Alam
Mr. Peng Zhang, The University of British Columbia (Presenter) Dr. Shahria Alam, University of British Columbia
Rack columns are generally made of thin-walled steel sheets, and the steel sheets are cold-formed into the desired cross-sections. The columns are utilised to form upright frames of a storage system and serve as compression members. Currently, the theoretical and experimental investigations of the buckling behaviour of ?-shaped rack columns with patterned holes are rare, and the analytical design solutions for predicting the compression capacity of these columns are not mature yet. This paper presents a theoretical study of the elastic buckling behaviour of rack columns under uniaxial compression, and three different ?-shaped cross-sections were investigated. The columns without holes are studied first; then, patterned holes are considered for the columns. Buckling curves and signature curves of the columns are generated by using a finite element software, ANSYS 18.1, and two different boundary conditions, i.e., simple-simple and clamp-clamp are considered. The buckling curves of the rack columns with holes, under the boundary condition of pinned-pinned, are generated as well. Three problems are mainly addressed here: (1) how to generate the signature curve of rack columns (without holes) by using conventional finite element programs (e.g., ANSYS); (2) what are the differences between the buckling behaviour of the columns with and without holes; (3) how to determine the critical buckling loads and critical buckling half-wavelengths of rack columns with holes accurately.
Evaluation the Seismic Behavior of Bridge Piers Utilizing Hybrid Reinforcements
Sherif Osman, Shahria Alam, Shamim Sheikh
Mr. Sherif Osman, The University of British Columbia (Presenter) Dr. Shahria Alam, University of British Columbia Dr. Shamim Sheikh, University of Toronto
Use of deicing salt during harsh winter is a critical factor that causes substantial deterioration of concrete infrastructure. In order to improve the performance of concrete against corrosion, Fiber Reinforced Polymer (FRP) bars were introduced. However, the challenge lies in its brittle nature of failure. Hence, in a seismically active region, FRP rebars cannot be used as reinforcement in the critical regions of concrete structures (Plastic hinge) unless it can be jointly used with a ductile material. In this study, double reinforced section is introduced which will be named hybrid reinforcement. Longitudinal rebars will be arranged into exterior (FRP) and interior (steel) cages. Two layers of transverse reinforcements, either made from FRP (for exterior cage) or steel (for interior cage), are also provided. The prescribed hybrid reinforcement is one potential alternative to mitigate such a problem. Currently, limited research has been directed towards identifying the nonlinear behaviour of hybrid reinforced concrete bridge piers. Investigating the yielding capacity, post-peak stiffness and curvature ductility is important to understand the non-linear behavior of the hybrid section.
To achieve this objective, the behavior of hybrid bridge piers will be experimentally investigated under quasi-static lateral load and axial compression on a scaled-down (1:2) models. A finite element model will be developed and validated against experimental results. The seismic behavior of the studied hybrid bridge piers will depend on six factors, including the concrete strength, total reinforcement ratio, FRP/Steel reinforcement ratio, FRP / Steel cage diameter ratio, FRP transverse volumetric ratio, and Steel transverse volumetric ratio. In this study, a factorial analysis will be performed by considering the effect of these six factors and their interactions on the seismic behavior of hybrid bridge piers. The expected outcome of this research is developing a new design tool, for hybrid bridge piers, to determine the load-deflection relationship, energy dissipation capacity, and strains in the longitudinal and transverse reinforcements under combined normal and shear stresses.
Performance-Based Design of RC Beams Exposed to Natural Fire: A Case Study
Robert Kuehnen, Maged Youssef, Salah El-Fitiany
Mr. Robert Kuehnen, Western University (Presenter) Dr. Maged Youssef, The University of Western Ontario Dr. Salah El-Fitiany, Alexandria University, Egypt
In North America, the current practice for structural fire safety involves the implementation of prescriptive methods, requiring compliance with passive fire-resistance barriers and active suppression systems. Although this approach has been largely successful in delaying the propagation of fire, which allows for the safe evacuation of occupants, it provides limited knowledge about expected structural behavior during fire. To ensure structural integrity, the North American industry is moving towards performance-based structural fire design, focusing on structural elements that can achieve specific performance objectives during fire exposure. Buildings can thus be designed with greater flexibility, reduced construction costs, and improved occupancy safety. Given the intrinsic fire-resistant properties of concrete, performance-based design is particularly powerful in the case of reinforced concrete (RC) structures.
In this paper, a case study is presented demonstrating a simplified approach to undertake performance-based flexural fire design of RC beams. The case study highlights the three main steps in the design process: (i) determination of the natural fire severity, (ii) calculation of element internal temperatures, and (iii) sectional flexure analysis. In each part, the process is performed using simplified analysis methods, which are validated against results obtained using experimental tests or computational finite element simulations. Using the outlined approach, engineers can design RC beams to withstand natural fire events.
Materials and structure env. load
Application of Agricultural - Waste Materials in Concrete: A Review
Sara Boudali, Ahmed Soliman, Sébastien Poncet, Stéphane Godbout, Joahnn Palacios, Bahira Abdulsalam
Dr. Sara Boudali, Concordia University (Presenter) Dr. Ahmed Soliman, Concordia University Dr. Sébastien Poncet, University of Sherbrooke Dr. Stéphane Godbout, IRDA Mr. Joahnn Palacios, IRDA Dr. Bahira Abdulsalam, CIISolutions Composites Infrastructure Innovation Solutions Corp.
High demand of natural resources and the disposal problem of agricultural wastes are two main challenges faced by construction and agriculture sectors. Therefore, the use of agro-waste in the construction industry can be an optimum solution. In response to the increased interest in sustainable construction materials, many agricultural waste materials are already used in concrete as alternative replacements for cement, fine aggregate, coarse aggregate and reinforcing materials. This paper provides an overview for the successful implementations of different agricultural waste materials to produce green concrete for different construction applications. It highlights the quantitative benefits of sustainable construction using agricultural waste materials and benefits of green materials in construction applications. This would allow engineers and policymakers to consider designing for sustainability as a new requirement in the design for publicly funded structures
CONTROL LOW STRENGTH AGRO-CONCRETE
Diba Ahadzadeh Ghanad, Ahmed Soliman, Stéphane Godbout, Joahnn Palacios
Ms. Diba Ahadzadeh Ghanad (Presenter) Dr. Ahmed Soliman, Concordia University Dr. Stéphane Godbout, IRDA Mr. Joahnn Palacios, IRDA
Agriculture farms produce a massive amount of wastes annually which represents one of the main challenges facing agriculture industry. This study attempt to link agriculture and construction industries through reusing such agriculture waste (Agro waste) in construction materials. Control low strength material (CLSM) was selected as a potential construction material that can accommodate a high percentage of agro waste. This is attributed to the fact that CLSM performance requirement is low enough to be achieved while incorporating Agro waste. Standard low strength material mixtures according to ASTM were used as reference mixtures. These mixtures were also modified by the incorporation of a fine agro waste at rates 5%,10% and 20% as a volume replacement for sand. Fresh and mechanical properties including mini-slump, water absorption, spread flow, compressive and tensile strengths, modulus of elasticity and shrinkage were evaluated for all mixtures. Results showed a reduction in mechanical properties, however, it was still within the targeted strength. In addition, the reduction in compressive strength and shrinkage has an indirect proportional to the increase in rate.
Effect of climate change on Canadian bridge Infrastructures
Hesham Othman, Luaay Hussein, Lamya Amleh
Ms. Hesham Othman, Ryerson University Dr. Luaay Hussein, Ryerson University Dr. Lamya Amleh, Ryerson University (Presenter)
Climate is changing. Extreme weather phenomena are now obvious, Global temperature increased by more than 2°C leading to the melting of the ice-pack at the North Pole. Moreover, The intensity and frequency of both precipitation and hurricanes have been changed dramatically over the last few years. These changes are substantially significant in the regions lies high latitudes compared to the rest of the world, including Canada, when compared with global trends. The rate of warming in Canada as a whole has been more than double that of the global mean, and that warming in northern Canada (i.e., north of 60°N latitude) has been roughly three times the global mean. Canada’s infrastructures could be at risk if actions are not taken to consider or adapt the climate change. The transportation networks, especially bridge infrastructures, can be considered as one of the most systems that will be affected by changing climate. The service life of such infrastructures is typically in the order of the time frame of the expected climate change scenarios (50 to 100 years).
Several parameters are considered in the design standards that depends either directly or indirectly on the climatic data, including: temperature, relative humidity, ice accretion, wind, and water loads. It should be pointed out that most current design climatic parameters are derived from historical data that goes back to the 1970’s time horizon. Thus, the existing and future infrastructures might face higher extreme climatic events than loads considered in the current practices.
This paper investigates the applicability of the current design climate loads of the Canadian Highway Bridge Design Code (CHBDC) to model current and future climatic actions. The studied climate loads include: daily temperatures (maximum, minimum, and mean) and hourly mean wind pressures (for return periods of 25, 50 and 100 years). First, the climatic design loads of CHBDC are compared with the current loads estimated based on homogenized climatic data from Environment Canada’s national archives for ten main Canadian cities. Thereafter, the future climate data are estimated for two different time horizons 2050 and 2100 use multi-model ensemble of projections, ranging from low to high emission pathways and compared to CHBDC values. The results showed that daily temperature parameters of CHBDC represent the current and future temperatures reasonably well. However, wind pressures that estimated based on actual climate data showed a significant difference in comparison to CHBDC, especially for coastal and north cities of Canada.
ELECTRICAL RESISTIVITY, PERMEABILITY AND MECHANICAL PROPERTIES OF RUBBERIZED CONCRETE
Sameh Hassan, Ahmed Soliman, Michelle Nokken
Mr. Sameh Hassan, Concordia University (Presenter) Dr. Ahmed Soliman, Concordia University Dr. Michelle Nokken, Concordia University
The application of crumb rubber from recycled tires has been used in construction as a replacement for the aggregate and fine sand in concrete. The use of these materials can improve the concrete performance and may enhance its properties along with minimizing the cost. This paper investigates the effect of 10% replacement of sand with fine crumb rubber on properties of concrete mixtures with and without silica fume. Compressive and tensile strengths, surface resistivity, and rapid chloride penetration tests were conducted. Results showed that the use of rubber without silica fume decreases the mechanical properties compared to the plain concrete, while it enhances concrete modulus. In addition, rubber had a marginal effect on the relationship between concrete mechanical properties and electric resistivity. Moreover, the rubber with silica fume had a significant effect on the electrical conductivity.
The Possibilities of Using the Agricultural Waste as Aggregate in Producing Sustainable Concrete
Sara Boudali, sameh hassan, Ahmed Soliman, Sébastien Poncet, Stéphane Godbout, Joahnn Palacios, Bahira Abdulsalam
Dr. Sara Boudali, Concordia University (Presenter) Mr. sameh hassan, CONCORDIA UNIVERSITY Dr. Ahmed Soliman, Concordia University Dr. Sébastien Poncet, University of Sherbrooke Dr. Stéphane Godbout, IRDA Mr. Joahnn Palacios, IRDA Dr. Bahira Abdulsalam, CIISolutions Composites Infrastructure Innovation Solutions Corp.
Concrete is the most widely used construction material. However, large volumes of natural resources and raw materials are being consumed in concrete production. This reduces concrete industry sustainability and increase its environmental negative impact. On the other hand, the agriculture sector is facing problems that require more efforts in agro-waste managements. To resolve this problem and binifit from agrowaste, in this study, the potential of using different types of agro-wastes in concrete as a total/partial replacement of aggregate will be evaluated. Three types of agro-wastes, which are categorized based on their fibrosity, fine and coarse, were tested. In addition, two types of binding materials, namely, ordinary cement and activated slag were used. Full characterization for different agro-waste and corresponding variations in compressive strength, density and microstructure were evaluated. Results showed that the compressive strength is directly affected by the physical properties of the incorporated agro-waste and the type of the binding material. Fibrous agro-wastes exhibited the highest strength with respect to other wastes. Successful use of such agro solid wastes as whole or partial replacement of natural aggregates contributes to energy saving, conservation of natural resources, and a reduction in the cost of construction materials.
Modular Construction & Sensing
Dynamic modeling of productivity in modular construction
Integration is a key to successful delivery of modular construction (MC). However, off-site construction is still fragmented which can be attributed to undesirable variances in productivity. Such variances are influenced by many factors, among which the potential of key performance indicators (KPIs) cannot be neglected. This study presents a system dynamics (SD)-based model for tracking productivity in delivery processes of MC. KPIs, pertaining to modular phases, are identified by developing KPI matrices through literature review from the perspective of modular manufacturers and general contractors. Data collected from a residential modular project constructed in Oslo, Norway. Causal loop and stock flow diagrams of productivity in MC are developed. The proposed model offers modular manufacturers and general contractors a flexible method for simulation of construction productivity in MC with the capability of finding causes of depicted variances. The core contribution of this research to MC literature is a developed dynamic productivity model which (1) integrates all modular phases for improving onsite construction productivity and (2) predicts onsite construction productivity by accounting for interdependent KPIs.
Feasibility Investigation and Accuracy Assessment for a New Generation UWB Tracking System
Tian Jin, Farnaz Sadeghpour, George Jergeas
Mr. Tian Jin (Presenter) Dr. Farnaz Sadeghpour, University of Calgary Dr. George Jergeas , University of Calgary
Safety issues are an inherent concern in construction sites and assuring a safer working environment is a never-ending endeavor in construction projects. Increasingly, the applications of Real Time Location estimation Systems (RTLS) in safety management in construction sites are studied. Ultra-Wide Band (UWB), as one of the RTLS systems, has demonstrated great suitability for construction site conditions due to its higher static and dynamic accuracies lower dependency on the Line-Of-Site, and less signal attenuation and multipath effect in comparison to other systems. Nonetheless, the difficulty of relocating and reconfiguration of the readers from one location to another, requirements for time cables between readers for the location estimation algorithms, as well as the large cost of the system, greatly decrease the practicality of its use on construction sites. Under this circumstance, a new-generation UWB RTLS has emerged that seems to overcome the shortcoming of previous systems. The system consists of devices that are much smaller in scale. The infrastructure is much simpler, with devices that can be used interchangeably as a reader or a tag. In addition, unlike older systems, the specific location estimation algorithm utilized in this system does not require time cables for time synchronization of anchors and tags. This is very desirable for construction sites as it greatly decreases interference with the movements on sites and increase the speed of relocating readers as the construction progresses. The system is also significantly less expensive compared to the older systems. Typically with RTLS, such conveniences come at the cost of lower accuracy or strength of signal. The objective of this study is to investigate the feasibility of using the new generation of UWB RTLS on construction sites and measure its accuracy compared with the older generations. The specific subobjectives of this study are to (1) measure the location estimation accuracy of the new generation UWB RTLS in both static and dynamic modes; (2) investigate the sensitivity of configuration variables such as the setup angle and distance between the readers; (3) investigate the impact of Line-Of-Site and signal blockage on its accuracies. An interpolation algorithm was developed for error distribution in static tests. For the dynamic accuracy, a robotic Total Station was synchronized and integrated with the system. The results of these experiments will be discussed in detail and compared with those from the older systems to draw conclusions on the applicability of the new generation UWB RTLS in construction sites.
Integrated scheduling of modular construction using “Mod-Scheduler”
TAREK SALAMA, Ahmad Salah, Osama Moselhi
Dr. TAREK SALAMA, CALIFORNIA STATE UNIVERSITY, Sacramento (Presenter) Dr. Ahmad Salah, Department of Civil and Construction Engineering, College of Engineering, Imam Abdulrahman Bin Faisal University, P.O. Box 1982 Dr. Osama Moselhi, Concordia University, BCEE
Opportunities and challenges for modular construction in developing nations: a case study in the Nepalese construction industry
Krishna Kisi, Nirajan Mani, Namhun Lee, Joseph Shrestha, Kishor Shrestha, Rujan Kayastha
Dr. Krishna Kisi, Central Connecticut State University Dr. Nirajan Mani, Fitchburg State University (Presenter) Dr. Namhun Lee Dr. Joseph Shrestha, East Tennessee State University Dr. Kishor Shrestha, Montana Technological University Mr. Rujan Kayastha
After the earthquake on April 25, 2015, in Midwestern Nepal, thousands of residential and commercial buildings were damaged. Subsequently, building owners started repairing and reconstructing their damaged buildings. Most of the reconstructed buildings in the cities are reinforced concrete frame structure, but such traditional construction technique is time-consuming and can be costly. Thus, owners and construction companies adapted modular construction as a suitable alternative. While there are benefits of modular construction, there are challenges that could hinder the broader adaptation of the technique. This study identified and ranked the opportunities and challenges associated with the modular construction technique in developing countries like Nepal. The opportunities and challenges were first identified based on literature review, and a questionnaire survey was developed to rank them based on the perspectives from contractors, architectures, engineers, and manufacturers/distributors that have direct or indirect experience and/or knowledge about modular construction in Nepal. Forty-two validated response were analyzed for this study. The top opportunities identified from this study include a reduction in the construction time; improved productivity; and reduced rework. The top challenges include the competition with the traditional construction techniques; the lack of information about modular construction in the society; and the lack of skilled workers. The findings are expected to aid the modular construction stakeholders in better understanding the opportunities and challenges that they can investigate. Such investigation can further lead to the identification of the solutions to the challenges and hence wider adaptation for the modular construction in developing countries like Nepal where the concept of modular construction is still new.
Novel experimental methods
Assessment of Code Provisions for Strength Determination of Aluminum Structures by Testing
Scott Walbridge, Laurent GÃ©rin
Dr. Scott Walbridge, University of Waterloo (Presenter) Mr. Laurent Gérin, University of Waterloo
Annex A14.1 of the CSA S6 Canadian Highway Bridge Design Code contains a formula and table for determining the design yield strength of unidentified structural steel by testing. The formula includes a 28 MPa correction for the difference between the “dynamic” and “static” yield strength. For aluminum structures, the American Aluminum Design Manual and the CSA S157 design code have similar formulas and tables for determining the ultimate strength of aluminum components by testing. The aluminum tables are believed to be inherently conservative in that they are established for a nominal aluminum strength based on a 99% survival probability, even though aluminum structures are then designed with a resistance factor that is the same as the one used for steel structures. CSA S6 Annex A14.1 and the associated resistance factors assume a 95% survival probability in establishing the nominal yield strength of the steel. Against this background, the proposed paper will present results of tension coupon tests used to investigate the existence of a difference between static and dynamic strength in aluminum using as-received and annealed samples of 5083 and 6061 alloy 9.5 mm thick plates. The results of these tests will be followed by a set of simple structural reliability analyses aimed at assessing the effects of the conservative assumptions made in the American Aluminum Design Manual and CSA S157. Given this information, a new formula and table will be proposed for establishing the strength of aluminum structures by testing.
Enhancing Asphalt Cement Properties Using Geopolymer- Based on Fly Ash and Glass Powder
Abdulrahman Hamid, Hassan Baaj, Mohab El-Hakim
Mr. Abdulrahman Hamid, University of Waterloo (Presenter) Dr. Hassan Baaj, University of Waterloo Dr. Mohab El-Hakim, Manhattan College
The severe Canadian winter conditions, together with the increase in traffic volumes play the major role in reducing the service life of flexible pavements. Rutting and cracking are probably the most common modes of pavement deterioration in Canada. These two modes forced researchers and engineers to develop several additives and solutions in order to improve the performance of paving materials. In this study, a critical literature review regarding the use of Geopolymers and their application in construction materials is provided. Moreover, an experimental work was conducted to study the rheological and microstructural properties of the PG 58-28 asphalt binder; with different percentages of Geopolymer; 0%, 3%, 6%, and 9%. The effect of Geopolymer curing time on rheological and microstructural properties was also investigated. Rotational Viscometer, Dynamic Shear Rheometer (DSR), and Environmental Scanning Electron Microscopy (ESEM) imaging devices were used to measure the performance of the different modified binders. Results indicated that the increase in the Geopolymer content and the curing time significantly affect the rheological behavior of the asphalt binder by increasing its viscosity, complex shear modulus and failure temperature. Samples with higher Geopolymer percentage exhibited better performance in terms of rutting resistance. Moreover, an improvement in the failure temperature is recorded as of 14.2% and 15.2% for 7 and 14 days curing times, respectively. Furthermore, increasing the percentage of the Geopolymer showed a development in the microstructure of asphalt binder whereby the asphalt binder with 9% Geopolymer showed larger fibril size as compared with the 3% and 6%. Undoubtedly, the Geopolymer has proved its ability to enhance the properties of the asphalt binder.
Keywords: Asphalt Cement, Rheology, Geopolymer, Master Curve, Workability, ESEM
Evaluation of proposed Steel Fibre Reinforced Concrete shear predictions against the Modified Compression Field Theory
Helmi Alguhi, Douglas Tomlinson
Mr. Helmi Alguhi, University of Alberta (Presenter) Dr. Douglas Tomlinson, University of Alberta
Steel fibre reinforced concrete (SFRC) is used in many applications in construction such as in shotcrete tunnel walls and slabs on grade. Compared to non-fibre reinforced concrete, SFRC has superior post-cracking performance which leads to elements with narrower crack widths. Narrower cracks enhance the service performance of beams and improve aggregate interlock, which increases the shear capacity of SFRC members relative to non-fibre reinforced concrete. However, the benefits of using SFRC are not incorporated into the design standard for concrete buildings (A23.3-14), particularly for crack control and shear resistance.
Numerous empirical models have been developed by researchers to account for the improvement SFRC has on shear resistance in concrete. However, many of these models are calibrated against limited test data, often only from tests performed by one researcher. This applicability of twelve different shear resistance models for SFRC was evaluated in this study using a database of 80 tests on shear-critical SFRC beams. These models were compared to a mechanics-based approach based on the Modified Compression Field Theory (MCFT). SFRC was incorporated into MCFT by modifying the tension constitutive models for concrete. The SFRC contribution is modelled by changing the concrete’s tension stress-strain response based on an inverse analysis of existing test data incorporating fibre material properties (tension stress-strain, end treatment (straight, hooked), diameter, length, and dosage. Fibre dosages between 0.5 and 2.5% were analyzed. Normal strength concrete (35 MPa) with 19 mm aggregates was the focus in this study. Steel and GFRP reinforced slabs and beams without stirrups, thicknesses ranging from 175 to 600 mm, and varying reinforcement ratios were evaluated.
In the MCFT analysis, it was seen that SFRC has smaller crack widths and enhanced aggregate interlock compared to non-fibre reinforced concrete. The effectiveness of SFRC increased with fibre dosage, particularly for fibres with hooked ends. The results show that SFRC is most effective at improving the shear resistance of members with lower reinforcement stiffness, particularly GFRP reinforced beams. Models that incorporate fibre reinforcement ratio, length, diameter, and end condition are more accurate compared both to test results and MCFT. These models are more suitable candidates for inclusion into future design standards.
INFLUENCE OF FUSED SILICA AND CASTING DIRECTION ON ASR EXPANSION
Sameh Hassan, Ahmed Soliman, Michelle Nokken
Mr. Sameh Hassan, Concordia University (Presenter) Dr. Ahmed Soliman, Concordia University Dr. Michelle Nokken, Concordia University
Alkali-silica reaction is a prevalent type of deterioration in concrete infrastructure. In laboratory testing, prisms are cast horizontally and subsequently tested for expansion in the vertical direction. This may not adequately relate to actual cast-in-place concrete structures. In this research, prisms were cast in horizontal and vertical directions. Both axial and transverse expansions were measured. Spratt aggregate and fused silica were used to hasten reactions leading to a clear monitoring for the influence of fused silica and casting direction. Results showed that the vertical casting was seen to increase the measured expansion by about 5-8% depending on the age of measurements. Moreover, the higher the fused silica, the higher the expansion regardless of the casting direction.
Key Word: Fused Silica, Alkali-Silica Reaction, Concrete, Aggregate, Expansion
Stripping assessment of asphalt coating using k-means clustering and support vector machines
Ehsan Rezazadeh Azar, Ashkan Sahari Moghaddam, Yolibeth Mejias, Heather Bell
Dr. Ehsan Rezazadeh Azar, Lakehead University (Presenter) Mr. Ashkan Sahari Moghaddam, Lakehead University Dr. Yolibeth Mejias, Ministry of Transportation Ontario Mrs. Heather Bell, Ministry of Transportation Ontario
Stripping of the asphalt coating is a major moisture-related damage in hot mix asphalt pavements, which deteriorates the bond between the asphalt cement and aggregate particles. This issue could initiate many forms of asphalt pavement distresses, namely ravelling. Static immersion is a common testing method to assess the stripping of asphalt cement cover from the aggregate particles in a submerged condition, but since this assessment depends on the visual judgment of technicians, its accuracy and reproducibility have been disputed by professionals and research community. Image processing and machine learning methods have proven to be reliable tools and have the potential to provide consistent and accurate results in this test. This paper introduces a computer vision-based system to estimate the stripping of test samples processed in the static immersion test. This system employs series of image processing methods to enhance the lighting of the images and to correct specular highlights. Then the pixels on the enhanced images are segmented using the k-means clustering algorithm, and the resulted clusters are classified using linear support vector machines algorithm to determine the number of pixels belonging to the coated and uncoated areas. A set of experiment was carried out to evaluate the performance of this system, in which the machine-measured results did not have a significant difference with the manual assessments with a mean difference of 4.9%.
The effect of emerging admixtures on the correlations between workability tests on mortar for 3D printing
Malo Charrier, Claudiane Ouellet-Plamondon
Mr. Malo Charrier (Presenter) Dr. Claudiane Ouellet-Plamondon, École de technologie supérieure
Additive manufacturing for cement-based materials is gaining interest these past years. Printing concrete has the potential to remove the time allowed to casting and molding. Nevertheless, new issues specific to 3D printing emerge. For example, the preservation of the mechanical properties and the stability of the printed layers. The objective of this paper is to identify the characteristics needed for a printed mortar to fulfill its role and propose a mixture that fills the required characteristics. A framework for testing several characteristics of mortar and cement paste are designed, and a small 3D printer prototype is made. The mixtures tested are composed of various combinations of superplasticizer (SP), accelerator (A), nanoclay (C) and viscosity-modifying admixture (VMA). After extracting the pore solution of the fresh cement paste using centrifugation its conductivity is measured. Viscosity is measured following the National Institute of Standards and Technology (NIST) method for Standard Reference Material 2492. The flow of the mortar is determined following the standard ASTMC1437. To propose a value of stability of the mortar the shifting of a fresh cylinder of 35 mm height and 60 mm diameter is recorded under a force of 100 N progressively applied. Finally, the percentage of the height decreasing of a printed mortar layer is computed after its curing period averaging six points on a 60 x 40 mm square in the center of the layer. The collected data are then compiled to train a regression model to predict the height decreasing of a printed mortar layer thanks to the results of the other experiments. Mechanical tests are conducted to study the hardened properties of the mortar. Finally, the aim is to be able to predict the physical measurement only with the composition of the mixture. Doing so, characteristics of printed mortar can be predicted before any test. Next steps are to increase the number of admixture to have a larger database and to validate the mix design to larger printed forms.
Novel materials and systems
Bond Behaviour of Steel Reinforcing Bars Embedded in Ultra-High-Performance Steel Fiber Reinforced Concrete
Rita Elizabeth Saikali, Dan Palermo, Stavroula Pantazopoulou
Ms. Rita Elizabeth Saikali, York University (Presenter) Dr. Dan Palermo, York University Dr. Stavroula Pantazopoulou, York University
This paper presents results from an experimental study conducted to understand the bond-stress slip behaviour of steel reinforcing bars embedded in Ultra-High-Performance Steel Fiber Reinforced Concrete (UHPSFRC). This emerging concrete is currently considered an optimal, durable material, which can substitute conventional concrete owing to its distinct fresh and hard properties. The compressive strength can reach 120 MPa, while the tensile strength is approximately 20 MPa defined by a strain-hardening behaviour. Thus, it is essential to understand the mechanism of stress transfer between this concrete and conventional reinforcement that permits the composite action of both materials. A four-point bending test program was arranged and conducted on 7 beams designed for the bond development to occur in the constant moment region along a short embedment length (5Db) in order to achieve a uniform distribution of bond stresses, enabling measurement of bond strength through reverse engineering of beam strength and deformation. Confinement was only provided by the concrete cover (equal to one bar diameter), whereas three design mixes were assessed and compared: two commercial and one developed in-house. The main difference between the mixes was the binder paste and the type of steel fibers, resulting in different flowability and tensile strength. Additional material testing was conducted on prisms under 4-point loading in order to extract the mechanical properties for all material mixes considered. The bond-specimens failed either by pullout or by cone formation with minimal deterioration of the concrete cover, illustrating the high confinement provided by the novel concrete surrounding the bar in tension. The bond strength was determined to be directly proportional to the tensile strength capacity of the design mix, where for the strongest material the bond strength was approximately 30 MPa. Moreover, the test results indicated a very ductile flexural beam response accompanied by significant mid-span deflection (more than 5% rotation capacity) and substantial bar-slip values. The test results demonstrated that an embedment length of five times the bar diameter is sufficient enough to yield the reinforcing bar.Â Thus, the high bond strength provided by the concrete cover enables significant reduction in the design development length as compared to what is used today for conventional concrete.
Cyclic performance of post tensioned steel beam column connection with end plates and shape memory alloy bars
Md Arman Chowdhury, Ahmad Rahmzadeh, Shahria Alam
Mr. Md Arman Chowdhury, The University of British Columbia (Presenter) Mr. Ahmad Rahmzadeh, The University of British Columbia Dr. Shahria Alam, University of British Columbia
Damage due to earthquake has become a major concern for both practicing engineers and researchers in the regions with high seismicity. Demolition of the whole structure rather than repairing is often the most economical solution in case of high residual deformation. High cost and time required for demolition and rebuilding can be a burden to the overall economy of a country. In a moment frame, permanent deformation after a severe earthquake can be eliminated by utilizing post tensioned (PT) self centering connections. In this connection, post-tensioning steel strands are used to pre-compress the beam to the column which introduces self centering capability to the connection. However, inelastic deformation in energy dissipating element is inevitable in this case. Cost and time are needed to replace energy dissipaters after each major earthquake. An innovative PT connection with shape memory alloy (SMA) can solve the above-mentioned problem. An end plated PT connection with the SMA bar is proposed and investigated in this study. Due to the superelastic property and large strain recovery, the SMA bar can sustain consecutive earthquake without any residual deformations. Although, no plastic strain remains in the SMA bar after load removal, energy dissipation capacity of this connection is comparatively low. To identify the optimized combination for the connection with sufficient strength, stiffness and energy dissipation, a parametric study is conducted. Preliminary design consideration is also suggested based on the numerical investigations.
Innovative Aluminum Pedestrian Bridges Case Study
Benoit Cusson, Jean-Denis Toupin
Mr. Benoit Cusson, WSP (Presenter) Jean-Denis Toupin
In 2017, WSP undertook the challenge of designing two non-conventional aluminum multifunctional walkways for Parks Canada. The designers retained the geometry of the early 19st railway bridges to recall the rich heritage of the industrial era. Aluminum was retained for the structures to emphasize that Parks Canada is looking towards the future with an innovative maintenance free material. Challenges during the design phase include vibration issues, stability of the top chord on elastic supports, ultimate resistance of welded aluminum, welds calculations and thermal expansion impact on multiple aspects.
The 27 m x 4,5 m pony-truss aluminum structures are completely welded and require no assembly on site which is a feat given the constraints imposed by this material. Welding procedures and assembly strategy at the factory will be discussed. Moreover, this case study will also explain how the aluminum top chord was bent to reproduce the typical deviation seen in old railway bridges. Details at the foundations like anchorage rods, bearing devices, and expansion joints will be described to demonstrate the importance of considering the galvanic corrosion issue when designing aluminum walkways.
Mechanical properties of hot-dip galvanized rectangular hollow sections
Hot-dip galvanizing is widely used for corrosion protection of steel structures. However, there has been a plethora of recent reports on premature cracking in galvanized steel structures, which have resulted in some early decommissions or even hazardous collapses. This research focuses on cold-formed Rectangular Hollow Sections (RHS). A total of 108 tensile coupons were tested to investigate the effects of galvanizing as well as different pre-galvanizing treatments on the material properties around the cross sections of the specimens. For the first time, this research reports a comprehensive measurement of residual stresses in different directions at the member ends which are directly relevant to the cracking issue. The results were also compared to the residual stresses far away from the member ends, which are relevant to structural stability research. In all, the research provides a better understanding of the characteristics and structural performance of galvanized RHS to facilitate its application. The recommendations can help engineers, fabricators and galvanizers mitigate the risk of cracking in RHS during galvanizing.
NUMERICAL INVESTIGATION OF THE LATERAL RESPONSE OF SINGLE AND DOUBLE CONTROLLED ROCKING STEEL BRIDGE PIERS
Ahmad Rahmzadeh, Faroque Hossain, Kamrul Islam, Shahria Alam, Tremblay Robert
Mr. Ahmad Rahmzadeh, The University of British Columbia (Presenter) Mr. Faroque Hossain Mr. Kamrul Islam, Ecole Polytechnique de Montreal Dr. Shahria Alam, University of British Columbia Mr. Tremblay Robert, Polytechnique Montreal
This paper presents a numerical investigation on the lateral behavior of controlled rocking steel bridge piers. The rocking behavior limits plastic straining in the column as the main cause of damage in the conventional counterparts. To achieve a positive post-uplifting stiffness, the pier is pre-stressed by a post-tensioned (PT) tendon. The system exhibits a self-centering property, unless local buckling occurs near the rocking interface. The lateral response of the system with various diameter-over-thickness ratios is explored using continuum finite element (FE) method. A macro model with two springs at extreme fibers of the column is developed and used to study the effect of modeling approach in the load-displacement behavior. Base and double rocking configurations are considered. It is shown that the simplified uplifting mechanism used in the macro model leads to an overestimation of the lateral load capacity and pre and post uplifting stiffness of the system. The double rocking configuration surpasses the base rocking in the stiffness, lateral load capacity and energy dissipation, however, exerts more demand on the tendon which might result in its failure.
Optimization & Construction Oper. (1)
Computing the Task Interruptions that Synchronize Task Delivery Speeds in Repetitive Projects
Tarek Hegazy, Kareem Mostafa
Dr. Tarek Hegazy, University of Waterloo Mr. Kareem Mostafa, University of Waterloo (Presenter)
Almost all infrastructure projects are repetitive in nature and require repetition of a set of identical or non-identical tasks along a number of units (e.g., sections of a linear highway, floors or a vertical high-rise, etc. ). Scheduling of these repetitive projects uses the project deadline to determine the tasks’ delivery rates and the necessary number of crews to achieve these rates. Efficient scheduling requires the crews to move from one unit to the other uninterrupted to minimize idle time and to maximize learning curve effects. While an ideal schedule would have all tasks following the same delivery rate, any rounding or use of pre-set crew limit disturbs the synchronized delivery rates and produces a schedule with intermittent delays. For example, in the case the successor task is faster than its predecessor, the successor task is given a later start date to maintain its work continuity, thus delaying the start of all the following tasks and possibly extending the project duration. In this case, researchers often introduce a designed task interruption to improve the synchronization of tasks’ delivery speeds, and help reduce project duration. Hence, optimal repetitive scheduling needs to strike the right balance between maintaining crew-work continuity to achieve cost savings (e.g., learning curve effect) and introducing task interruptions to achieve shorter project duration. Such a compromise motivated many researchers to consider work interruption as a variable in the larger scheme of schedule optimization, as opposed to having work continuity as a hard constraint. Because schedule optimization problems already have a high number of variables (e.g., construction options, number of crews, etc.), they are classified as NP-hard problems where the increase in variables produces an exponential increase in the number of possible solutions. Conversely, reducing the number of variables would substantially decrease problem size and increase the possibility of finding near optimum solutions to problems. This paper, therefore, aims to developing and testing a general mathematical formulation to compute the optimal work interruptions scheme (in magnitude and frequency) without incorporating them as variables in schedule optimization. The paper starts with a literature review of existing studies on interruption time for repetitive projects, followed by a generic mathematical formulation of interruption time, given the tasks’ delivery speeds and permissible number of interruptions. Experimentation with a spreadsheet program is then presented to demonstrate the use of the proposed formulation and its benefits in facilitating schedule optimization for variety of project sizes.
Performance-based Contracts Optimization for Enhanced Roads' Condition
Soliman Abu-Samra, Luis E Amador-Jimenez
Dr. Soliman Abu-Samra, KPMG Canada (Presenter) Dr. Luis E Amador-Jimenez , Concordia University
Performance-based contracts (PBC) for highways are increasingly becoming an attractive mechanism for transferring traditional public sector activities to private duties. Increased financial pressures on governments, user demands for improved service levels, and the operational efficiencies offered by the private sector, all create a strong business case for PBC. To enable municipalities and private sector investors engage in PBC, there is a need for quantitative tools that allow both entities: (1) structure the PBC in terms of risk allocation, (2) develop appropriate levels for service penalties and incentives in the contract, (3) define appropriate targets for highway level of service, and (4) determine the most cost-effective set of maintenance and rehabilitation (M&R) activities. This paper develops a series of mathematical optimization models that allow municipalities (pre-contract) to define: (1) performance indicators; (2) their threshold levels; and (3) appropriate penalties’ and incentives’ levels. Furthermore, its ability is expanded for post-contract decisions such that; it aids maintenance contractors in selecting the optimal M&R plan for both project and network-levels while minimizing the Life-Cycle Costs (LCC) and meeting the performance indicators’ limits. The developed system extends the typical functionality of traditional pavement management systems to cover specific PBC contractual requirements. It revolves around four models: (1) asset inventory, which includes all the necessary physical, climatic, and traffic information, (2) deterioration models; where defect-specific pavement deterioration models are developed using multivariate regression and stochastic network-level deterioration models are developed using markov chains, (3) life cycle costing models; which are developed to cover specific financial obligations in PBC like penalties and incentives, in addition to traditional M&R expenditures, and (4) optimization engine; where genetic algorithms was used to trade-off various decisions. The models were applied to a 100-km rural highway in the Northeastern Egyptian governorate and the results showed the drastic effect of the penalties/incentives limits on the LCC and Pavement Condition Index (PCI), displaying a 12% increase in the LCC with 4% improvement in the PCI. Furthermore, the sensitivity analysis exposed the considerable effect of the limits’ variability among the M&R costs, penalties/incentives values, and PCI. A 17% increase in the penalties and an 8% decrease in the incentives resulted in a 17% increasing in the LCC while reaching 91% PCI. In conclusion, the developed system is an effective tool for municipalities and contractors to make informed pre-contract and post-contract decisions on their approach to contractual risk allocation and M&R planning respectively.
Trilevel Optimization Framework for Municipal Co-located Infrastructure: City of Montreal
Soliman Abu-Samra, Luis E Amador-Jimenez
Dr. Soliman Abu-Samra, KPMG Canada (Presenter) Dr. Luis E Amador-Jimenez , Concordia University
Municipalities are experiencing high inefficiency and financial burden imposed by their under-performing infrastructure. One-third of Canada’s municipal infrastructure are in fair, poor and failing condition states, increasing the risk of service disruption and leaving the decision-makers with no choice but undertake immediate interventions. Furthermore, the massive number of infrastructure intervention activities occurring in cities leads to detrimental social, environmental, and economic impacts on the community. Thus, coordinating the interventions of the co-located assets (i.e. roads, water, and sewer) to reduce the duplicate activities, service disruptions, and corridor rehabilitation cost, is progressively becoming of paramount importance to cope with those tough challenges. Numerous attempts were made by previous scholars to enhance the infrastructure performance within the limited budget. Yet, most of their efforts were geared towards short-term intervention planning for a single asset, without accounting for the potential coordination benefits and savings. Thus, this paper develops a tri-level goal optimization framework to coordinate the intervention planning and efficiently allocate the funds among the co-located assets. The framework revolves through five models: (1) asset inventory, which comprises the asset characteristics of the corridor infrastructure; (2) deterioration and future condition models, which relies on probabilistic Weibull models to obtain the reliability of the co-located assets and account for the uncertainties across the assets’ life-cycle; (3) financial model, which computes the direct and indirect costs for interventions and service disruptions; (4) temporal model that computes the disruption time for different intervention scenarios; and (5) Tri-level optimization model that features an integrated non-pre-emptive goal optimization and genetic algorithm engine to maximize the financial, reliability, and temporal improvements, as opposed to the conventional infrastructure management approach. The tri-level hierarchy is similar to the management levels (i.e. strategic, tactical, operational) such that; the number of systems represents the strategic level; the systems represents the tactical level; and the interventions’ types represent the operational level. It revealed huge search space savings, estimated at 720*25, as opposed to conventional optimization techniques, assuming 20 corridors, with 2 intervention types, and 25 years planning horizon. The system was applied to a 9-km stretch on the city of Montreal network and the optimized intervention schedule exposed promising results as opposed to the heuristic-based with an overall improvement of 10% broken-down into 11%, 7%, 6%, for the reliability, life-cycle costs, and time. The developed framework facilitates the decision-making process for planning the corridor infrastructure interventions.
Understanding the Water-Energy Nexus in Urban Areas: A Cluster Analysis of Urban Water and Energy Consumption
Lufan Wang, Nora El-Gohary
Ms. Lufan Wang, University of Illinois at Urbana-Champaign (Presenter) Ms. Nora El-Gohary, University of Illinois at Urbana-Champaign
The rapid urbanization and population growth are changing the global water- and energy-use patterns. A better understanding of the complex interactions between the urban water and energy systems is crucial in developing healthy, resilient, and sustainable cities. Although the water-energy nexus has attracted much research attention in recent years, substantial knowledge gaps still exist. There is still a limited understanding of the interrelationships between urban water and energy usage. First, most of the existing efforts analyzed water and energy usage separately. Second, they used a limited number of cases in their analyses. Towards addressing these knowledge gaps, this paper proposes a data-driven methodology for identifying and understanding the different water and energy consumption patterns of cities. A cluster analysis of 89 U.S. cities was conducted, taking socioeconomic factors (e.g., population, median household income, and total number of housing units), local climate conditions, and water and energy consumption data into account. The results show that the cluster analysis can help identify and characterize urban water-energy consumption patterns. These patterns could provide insights to support water-and-energy decision and policy making.Â
Optimization & Construction Oper. (2)
A multi-Objective Model for Enterprise cash Flow Management
Ahmed Shiha, Ossama Hosny
Mr. Ahmed Shiha, American University in Cairo (Presenter) Dr. Ossama Hosny, AUC
Research on Finance-based scheduling has been receiving increased interest from construction contractors to support them in managing their projects’ cash flow. Failure to efficiently manage cash flow, on a project level, diminishes the Contractor’s profitability and undermines project’s viability. Moreover, Construction contractors usually work on multiple projects concurrently which need careful analysis of the effect of each project on other projects. Management of cash flow includes both management of cash inflows and outflows, as well as administration of positive and negative cash requirement. The most challenging issue for the enterprise is to properly schedule cash inflows and outflows to cover any shortage and ensure smooth execution of projects. Construction projects involve multiple parties that affect the cash flow: Contractors, Owners, sub-contractors, suppliers, and banks. Contractual and financial arrangements between these different parties affect cash flow obligations. Contractors often rely on loans from banks to finance a portfolio at certain stages. Such reliance implies different parameters such as interest rates as well as when to apply for loans that eventually affect the Contractor’s profitability. This paper highlights Employer’s payments to contractor, Contractor’s payments to subcontractors and suppliers, as well as Contractor’s financial arrangements with banks as the main payment conditions relied upon in accurate modelling of portfolio cash flow management. A multi-objective optimization model that uses genetic algorithm is presented in this paper to support decision makers in construction companies to reach the optimum projects’ schedules’ that minimizes the total interest paid by the Contractor during the portfolio as well as minimizing the maximum negative cash flow, while accounting for various payment conditions between multiple involved parties. Many researches concentrated on modelling finance-based scheduling highlighting Owner-Contractor payment terms only at a project level. The novelty in the proposed model is the inclusion of different financial terms such as advance payments, and retention between Contractor-subcontractor interest rates between Contractor-bank as well as the flexibility of the model to include any number of projects within a portfolio, number of activities within a project, and any number of predecessors for each activity. The proposed improved model targets enhanced cash flow management of Contractors to maximize their profitability and internal rate of return at a company level.
Implementation of Blockchain Technology in the Construction Industry
Jason Hailer, Steven Graham
Mr. Jason Hailer, Cal Poly - SLO Mr. Steven Graham, MATT Construction (Presenter)
In general, the construction industry has been pretty resistant to change. While most industries have gained in productivity over the years through implementation of new technologies and other factors, construction industry productivity has been on a steady decline since the 1960s. Even though there are a multitude of reasons for this, including more complex building types and a decline in the workforce, the major problem holding construction back are project management issues and alienation of project stakeholders in the construction process. Some improvements have been made to help with collaboration between parties, like building information modeling (BIM) and project management software like Procore and Plangrid, but there isn’t one application that pools information to share data between parties.
Blockchain can make a difference and help solve the construction industry’s collaboration problem. Blockchain is a peer-to-peer, controlled, distributed transactional database used to record and store lists of transactions (called blocks) that are verified through cryptography. A relatively new technology (created in 2008 by Satoshi Nakamoto), blockchain research, especially in the construction field, is almost nonexistent. In fact, only a handful of articles were published on this subject, most of them based on theories and assumptions and only a handful of forward thinking companies putting it into practice. Since there has not been a substantive amount of research done on the convergence of blockchain and the construction industry, the construction industry is not aware of the technology and its potential benefits. Since the industry is historically resistant to change, the consideration of an emerging and potentially disruptive technology is daunting. The research conducted in this paper explores the emergence of blockchain, highlights progressive companies implementing this technology in construction, and analyzes the best practices and applications needed for blockchain to succeed in the construction industry.
Improving the 3Ps in construction projects with a focus on customer experience
Quality is gradually becoming a measure to assess organizations that will succeed in any particular industry. Quality has many definitions, but in construction, it has mostly focused on satisfying the customers' requirements. This approach to quality is focused on "technical" requirements, which may be seen as important to the project, but nowadays satisfying customers' "technical" requirements may not be enough to bring about repeat business or customer loyalty. This tends to indicate that total customer experience throughout the lifecycle of the project is essential to customer loyalty. Although Total Quality Management (TQM) emphasizes the importance of customer focus, there is limited research in the construction sector as to what customer experience involves. This research uses a qualitative approach to investigate the aspects that make up customer experience in the construction industry. It also presents various aspects that construction companies will have to plan for, to ensure that they improve the 3Ps (people, products and processes) to achieve better total customer experience. This research study provides valuable information that will enable design and construction professionals to improve quality in their projects by having an understanding of customer experience.
Lean Design in construction industry: From theory to practice
hafsa chbaly, Forgues Daniel, Samia Ben Rajeb
Mrs. hafsa chbaly, école de technologie supérieure (Presenter) Dr. Forgues Daniel, Ecole de technologie supérieure Mrs. Samia Ben Rajeb , COLLAEB - Université libre de Bruxelles
While Lean Design originates from Toyota Production System, it has been implemented to the construction industry in order to maximize value of customers and to reduce waste through providing a better alignment between architectural solutions and customers’ needs and requirements. However, such an alignment is difficult to reach when the project is complex due to the involvement of different stakeholders in the design process.
This paper provides a literature review of over 70 published research articles regarding Lean Design through the last ten years from 2007 to 2018. The review is based on, first, a comparison between different definitions and terminologies presented by authors, and second, on an analysis of how Lean Design methods and tools are applicable to the construction industry. Two main issues have been identified and exposed in this literature review.
Indeed, there is still a gap between theory and practice in relation to the context of construction industry. One aspect of this gap is reflected by the lack of a standard definition of what Lean design means. Another aspect is the lack of consensus on a clear terminology of Lean Design. In fact, we found four different terminologies: Lean Design, Lean Design Management, Lean Design Process and Lean Design and Construction. In addition, there is a lack of alignment between the objectives of Lean Design and the methods or tools used in practice. This is partly due to the fact that methods and tools of this approach often come directly from the manufacturing industry, without having a clear explanation about how they could be implemented in a practical context or adapted to the design process.
Thus, the main contribution of this research consists in providing the reader with a comprehensive state of the art on Lean Design and an analysis and discussion about the limitations and challenges facing current applications of Lean Design in the construction sector.
Key Words: Lean Design, Lean Design Process, Lean Design and Construction, Lean Design Management
THE RELATIONSHIP WITH THE BOSS IN PROJECT-BASED INDUSTRIES
M. Hossein K. Jamali, Avi Wiezel
Dr. M. Hossein K. Jamali, ASU (Presenter) Dr. Avi Wiezel, ASU
The research question addressed in this paper is: “How much does an individual's relationship with the boss influence his/her relationships with peers, subordinates, and others that contribute to the individual’s success?” Current literature focuses exclusively on the boss (direct supervisor), but overlooks other contributors that add to the success of the individual. In this research, other contributors - referred to as stakeholders - are also studied. It examines the correlation between quality and importance of the relationship, as well as the time an individual spends with each stakeholder. This research analyzes the influence of the boss-employee relationship (BER) by using a self-diagnostic exercise called “Who’s on Your Molecule” (WOYM). In this work, we collected WOYM data through leadership seminars offered by the Construction Industry Institute, which is a consortium of owner, engineer-contractor, and supplier firms from the public and private sectors (CII). Data for this research was collected from 327 project personnel at a level commensurate with Project Manager (PM) or assistant PM. Participants were from 16 companies that are members of the Construction Industry Institute. The data for the research was collected using a unique data-collection method embedded in leadership seminars offered by the CII. Results show that contrary to expectations set up in the literature, the boss-employee relationship is not a driving factor in other employee relationships. Additional variables and findings are also seen to influence overall quality of relationships of an employee in the workplace.
Comparative Analysis of Reaction Kinetics of One and Two Parts Geopolymers
Wala'a Almakhadmeh, Ahmed Soliman
Ms. Wala'a Almakhadmeh, Concordia University (Presenter) Dr. Ahmed Soliman, Concordia University
W. Almakhadmeh1 and A.M. Soliman2
1. PhD student, Department of Building, Civil and Environmental Engineering,
Concordia University, Montreal Quebec Canada
2. Assistant Professor, Department of Building, Civil and Environmental Engineering,
Concordia University, Montreal Quebec Canada
Alkali-activated materials (AAMs) are recognized as potential alternatives to ordinary Portland cement (OPC). AAMs have a low carbon dioxide emission as well as consume industrial byproducts instead of sending to landfilled. Concentrated aqueous alkali solutions is used to start the activation process of the solid aluminosilicate precursor and form the binding material in AAMs. Alkali activate slag is one of the promising AAMs, however, its high drying shrinkage strain is one of the main disadvantages. Effect of varying the silica modulus (Ms) with 4% concentration of alkaline activator Na2O% has been investigated. Fresh and hardened properties, including setting time, heat of hydration, compressive strength, and drying and autogenous shrinkage tests were evaluated for all tested mixtures. Results show that increasing Ms shortened the final setting time, and increased the 28 days’ compressive strength. Correspondingly, the autogenous and drying shrinkage also increase as Ms values increased. This highlighted the importance of controlling the Ms value to achieve adequate strength while maintaining lower shrinkage.
Key Words: Silica modulus, Cement, pastes, Alkali activated slag; Heat of hydration.
Effect of Sodium Oxide on the Properties of Alkali-Activated Slag Mortars
Wala'a Almakhadmeh, Ahmed Soliman
Ms. Wala'a Almakhadmeh, Concordia University (Presenter) Dr. Ahmed Soliman, Concordia University
W. Almakhadmeh1 and A.M. Soliman2
1. PhD student, Department of Building, Civil and Environmental Engineering,
Concordia University, Montreal Quebec Canada
2. Assistant Professor, Department of Building, Civil and Environmental Engineering,
Concordia University, Montreal Quebec Canada
Despite the promising mechanical and eco-friendly performance of alkali activated slag (AAS), shrinkage of AAS is considered as the most significant challenges hindering its implementation. It seems that there is a clear gap between the measured performance inside the lab and actual performance in-situ of alkali-activated materials. Shrinkage cracking can dramatically reduce the durability of any concrete member. Hence, a comprehensive understanding of the mechanism of the shrinkage in AAS, and effectiveness of different mitigation techniques are essential to prevent these damages in future. In this paper, an overview is presented on the mitigation strategies and their effectiveness in reducing AAS shrinkage. This would allow engineers to select the suitable mitigation technique for different applications.
Key Words: Alkali activated slag; shrinkage, mitigation techniques
Effectiveness of concrete filled steel jackets for RC columns
Saadeldin Mostafa, Mohamed N. Abou-Zeid
Mr. Saadeldin Mostafa (Presenter) Dr. Mohamed N. Abou-Zeid, The American University in Cairo
Repair and strengthening techniques of RC elements are considered to be challenging due to time, cost, and space constraints. Conventionally, several techniques have been used in the retrofitting of RC element. These techniques includes epoxy repair, concrete and steel jacketing and FRP. Recently a new technique has been introduced in some cases which is concrete filled steel jackets. Although the previously mentioned techniques have been thoroughly studied, this technique has not been studied in literature. Consequently, more data is required for a safe and economic design of this technique.
In this work, a repair/strengthening technique for RC columns is proposed which is concrete filled steel jackets. This technique comprises a steel cage consisting of four steel angles with steel strips at fixed spacing to prevent the buckling of the angles. The space between the RC column and the steel cage is filled with different classes of concrete.
The experimental program consisted of ten RC columns, two of them are unstrengthened columns. Eight steel cages were used with the same length of the column to confine the RC columns. Four different concrete mixes of filling concrete were prepared with different grades to be used as the filling concrete. No interface or shear connectors were used between the old and new filling concrete. LVDTs and strain gages were mounted on the specimens to record the load displacement and stress strain curves of the specimens. The properties of hardened concrete mixes were assessed using their cube strength at 28 days. The specimens were then uniaxially loaded till failure. Afterwards, the results of jacketed specimens were compared with each other as well as control specimens (i.e. specimens without jacketing).
In order to address the effect of the composite jacketing, the strength of the columns are to be compared with the Eurocode 4 design equations for composite sections. It is expected that this work will achieve a better understanding of the behavior of this composite system in terms of strength and ductility. As well as exploring the most appropriate concrete class to be used with this proposed technique.
FLEXURAL BEHAVIOR OF RECTANGULAR CONCRETE FILLED FRP TUBES (CFFT) BEAMS POST TENSIONNED WITH STEEL CABLES
Asmaa Ahmed, Mohamed Hassan, Radhouane Masmoudi
Ms. Asmaa Ahmed, Université de Sherbrooke (Presenter) Dr. Mohamed Hassan, Université de Sherbrooke Mr. Radhouane Masmoudi, Université de Sherbrooke
The concept of concrete-filled fiber-reinforced polymer (FRP) tubes (CFFTs) is promising for a variety of structural applications and a good alternative for innovative constructions because of numerous attractive features, including durability and concrete confinement. In applications where the design of a structural member is governed by large flexural loads, such as in the case of marine (fender) piles and bridge girders, laboratory and field bending tests have shown that CFFTs can match the bending strength of similarly sized conventional prestressed and reinforced concrete (RC) members. After cracking, however, CFFTs have lower flexural stiffness, which results in large deflections. The lower flexural stiffness is due to the low Young’s modulus of the FRP tubes. One way to counteract the effects of this lack of flexural stiffness is to apply longitudinal post-tensioning, which will also activate the confinement mechanism induced by the FRP tube and would lead to considerable enhancement. Also, the using post-tensioning in combination with FRP Tube confinement may lead to a better control of service limit states and reduce the size of the structural member. This paper presents the test results of an experimental study aimed at investigating the flexural behaviour of rectangular post-tensioned concrete filled FRP tubes (PCFFTs) beams. A total of three full-scale PCFFT and one control conventional RC CFFT beams with 3300 mm long and 305×406 mm2 cross section were constructed, instrumented and tested under a four-point bending load. The test parameters are: the level of post-tension in the steel cables and the FRP tube thicknesses. The experimental results showed that introducing post-tensioning to the CFFT beams substantially enhanced the flexural strength as well as the serviceability requirements of the tested beams. In addition, the flexural mode (tension or compression failure) was finally governed by the FRP tube thickness.
Climate Change and Its Impact on Coastal Cities: A Case Study from Alexandria
Hend Ismail, Mohamed N. Abou-Zeid
Ms. Hend Ismail, The American University in Cairo (Presenter) Dr. Mohamed N. Abou-Zeid, The American University in Cairo
Throughout history, coastal cities have been influential and attracted large population due to their rich resources, eco-social and cultural transfer. Today, such privilege is questionable as coastal cities are facing high risk to be significantly damaged if not swiped away due to Sea Level Rise and floods resulting from climate change. As such, millions of urban inhabitants in low and middle-income nations are at risk from direct and indirect impacts of climate change. Moreover, climate change when left undealt may contribute in forcing migration, conflicts, hunger and destroy infrastructure. Sad but true, Egypt is ranked 3rd on the list of countries most affected by climate change. The effects include temperature rise, change in rain patterns, rise of sea level, and increase in catastrophic weather events with all socio-economic consequences. Alexandria, is listed among the 15 of the world’s 20 coastal megacities that are at risk from SLR and coastal surges. However, such threats can be minimized through; ‘mitigation’ where causes can be controlled and ‘adaptation’ where cities can be protected.
The objectives of this study are to uncover and assess negative impacts of climate change on coastal cities and its built environment globally, and particularly in Alexandria. Also, the vulnerability of its residents and their level of awareness; identifying the gaps in Egypt National Climate Change Strategy that triggers the city’s sustainability. Additionally, explore design parameters that promote sustainable design for buildings in areas at high risk; assess the perception and knowledge of architects, engineers and policy makers on issues related to climate change and buildings. In order to fulfill these objectives, an intensive literature study and hybrid methodology were undertaken. Two questionnaires were developed for Alexandria’s residents, and architects and engineers; one to one interviews with experts, governmental and NGOs representatives.
The findings of this study reveal and confirm the high vulnerability of the residents due to the inefficient practices, weak and poor communication between the government and the residents. Also, it pinpoints poor and limited knowledge for sustainable practices and designs that need to be adapted to climatic threats. Gaps in Egypt National Climate Change Strategy were identified. Looking forward, a recommended design guideline based on mitigation and adaptation practices have to be established in lights of the findings of this work. Such recommendations need to be transformed in the soon future into an action plan nationwide.
Keywords: Climate Change, Coastal City, Alexandria, Sea Level Rise, Mitigation, Adaptation
COMPARATIVE STUDY OF THE HEC-RAS, IBER AND FLOW 3D SOFTWARES IN STUDYING FLOW CARACTERISTICS ACROSS A DYNAMIC MEANDER IN COLOMBIA
Juliana Vargas, Leonel de Jesus Rivera Grisales, Alejandro Salazar, Valentina Robledo, Philippe Chang
Mrs. Juliana Vargas, Universidad Nacional de Colombia (Presenter) Mr. Leonel de Jesus Rivera Grisales, Universidad Nacional de Colombia Sede Manizales Mr. Alejandro Salazar, Universidad Nacional de Colombia Mrs. Valentina Robledo Dr. Philippe Chang, Universidad Nacional de Colombia Sede Manizales
La Dorada Township (Caldas, Colombia) is located mid-way upstream along the west bank of the Magdalena River. In this region the channel banks have been affected by severe erosion as a consequence of the flow dynamics across a series of meanders. This work presents a comparative analysis of the HEC-RAS, IBER and FLOW 3D softwares as they are implemented in the characterization process of the channel flow dynamics, assessing their capabilities and limitations. Two field campaigns were completed in the region in February and May 2018 over the dry and rainy seasons respectively and included topographical and bathymetric surveys and river bed samples collection. Modelling of the river stretch was undertaken using a digital elevation model and field data. The three hydraulic models were prepared considering equivalent 1D, 2D and 3D conditions hence comparing simulated results with field data. The study results highlighted the limitations and applicability of the latter in correctly modeling secondary currents across a curved channel and non-hydrostatic pressure conditions. Specifically the study points to: i) the validity of a 1D model if specific conditions related to channel characteristics and discretization of the domain can be met; ii) the shortcoming of the 2D shallow water equations in such case, and its inability to determine a non-zero, constant vertical velocity component across the channel depth; and iii) the requirement of a 3D model to correctly reproduce the three-dimensional velocity field distribution necessary to explain specific erosion processes occurring in meanders for example.
Numerical model of the chloride transport by capillarity effects in cement materials
Thomas Sanchez, David Conciatori , Francine LaferriÃ¨re
Dr. Thomas Sanchez, Laval University (Presenter) David Conciatori Dr. Francine Laferrière
Reinforced concrete infrastructure subjected to wet-dry cycles is deteriorating at an accelerated rate. The transport of chloride ions, responsible for the corrosion of the reinforcements in these materials, is not only due to diffusion but also to the effects of water transport and capillarity. These two last phenomena are currently very poorly modelled. This work therefore aims to create a numerical model of multi-species and reactive transport of chlorinated ions by capillarity in a cementitious material. The main difficulty encountered in measuring capillary suction is the great complexity of obtaining experimental data. Indeed, a capillary test only makes it possible to obtain the concentration of chloride that has penetrated after a certain time. It is then necessary to carry out several of them under the same experimental conditions to obtain an evolution of the penetration of chloride ions. This study is based on innovative experimental work recently carried out (Conciatori et al., 2010): capillary tests with a chloride sensor inserted inside the cementitious matrix to measure the evolution of chloride concentration over time at a given penetration depth. During this study, simulations with the TransChlor prediction software had been carried out but did not allow to accurately simulate the phenomena involved by the experimental curve. One possible explanation is that the software used is uni-species and does not consider chemical reactions in a phenomenological way.
In the proposed article, we thus created a numerical model under the PhreeqC multi-species reactive transport software capable of modelling chloride transport during a capillarity test by a Reactive, Advective and Dispersive law. The model considers the diffusion of chlorinated ions and water transport by capillarity, as well as the chemical reactions that occur between the ions and the cementitious matrix in a phenomenological way. In larger perspective, this study let to improve knowledge in concrete durability structures in severe environmental condition and the numerical model that can be created to predict their life service to better maintenance.
Conciatori, D., Laferrière, F., Brühwiler, E., 2010. Comprehensive modeling of chloride ion and water ingress into concrete considering thermal and carbonation state for real climate. Cem. Concr. Res. 40, 109–118. https://doi.org/10/bd9q4n
Optimal maintenance plan for a vibrating-grate biomass boiler: availability and cost saving approach
Mohammad Hosseinirahdar, Fuzhan Nasiri, Bruno Lee
Mr. Mohammad Hosseinirahdar, Concordia University (Presenter) Dr. Fuzhan Nasiri, Concordia University Dr. Bruno Lee, Concordia University
In recent years, political and economic issues motivated Canada government to make northern Canada more crowded. To hit this aim, it is vital to make these regions more energy secure since they are off-grid and consequently the long harsh winter worsens this situation. Currently, diesel generators mostly provide demanded energy through the remote areas in Canada while high capital and operational cost of system burden government and people. By brainstorming through available energy technologies, Biomass boilers can be pondered as a promising technology for such these areas particularly through areas far from source of diesel fuel. However, having the system available during the long winter plays a key role to ensure us about energy security. A mathematical optimization of the maintenance plan regarding a vibrating-grate biomass boiler, which is the case study in this paper, is carried out based on the system availability so that the maintenance cost is minimized while the system availability remains higher than initial availability. A modified failure density function is utilized to bring the maintenance effect to component reliability following the maintenance. A regression analysis is performed on the constant hazard rate to turn them into Weibull distribution parameters (?, ?) to form a time-dependent hazard functions. To examine the system availability mathematically, Fault Tree (FT) method is employed and since only series and parallel arrangement exist through the system, this method is most proper one in this case study. A flowchart of maintenance optimization is designed to optimize the system availability function with 33 unique components and results shows 32% decay in the number of maintenance tasks over 10 years of operation. The flowchart performs fast and efficient somehow that it promises to stay efficient even for more complex system.
Time-depende of TBBPA accumulation on long-term used biochar
TBBPA is a kind of widely used toxic brominated flame retardant both in market and construct materials. Biochar (black carbon), as produced from cheap agriculture wastes via pyrolysis, often play an important role to improve field fertility, soil microbe activity and prevent leaching from disposal sites. To investigate pollutant accumulation on long-term used biochar, the adsorption on aged biochar was studied concerning kinetics, adsorption rates and adsorption mechanisms. The SEM image of long-term used biochar exhibits surface aging process as the surface grows more valleys and channels. The long-term used biochar also shows higher adsorption rates and better adsorption performance than original biochar. The correlation of surface area and adsorption rate indicates that the high adsorption on long-term biochar can be attributed to high surface area. According to the peaks in FTIR spectra, the adsorption of TBBPA favors the hydroxyl interactions, and the long-term used biochar has more hydroxyl groups for the adsorption, which suggest another explanation of TBBPA accumulation on long-term used biochar. Thus, the long-term used biochar has higher capacity of TBBPA adsorption, resulting in constant accumulation process of TBBPA and related organics, which can involve a potential threat for soil poisoning and unexpected pollutions. Â
Wind-induced pressure for Silsoe cube tested in the wind-induced damage simulator
ZHE XIAO, Elena Dragomirescu
Mr. ZHE XIAO, University of Ottawa (Presenter) Dr. Elena Dragomirescu, University of Ottawa
Wind-induced pressure for Silsoe cube tested in the wind-induced damage simulator
University of Ottawa
Zhe Xiao, Elena Dragomirescu
A new wind testing facility, the Wind-induced Damage Simulator (WDS), was designed and built at the University of Ottawa. The new facility is capable of generating extreme wind conditions and can achieve high pressure testing environment for scaled models as well as full scale structural elements such as: roofs, windows and curtain walls. The WDS system has total dimensions of 3.65 m x 3.65 m x 3.0 m and has 20 circular inlet openings on the four lateral walls. The outlet of the box with a diameter of 300 mm, is at the center of roof and it is connecting to a powerful industrial blower through a steel made duct. A model of the Silsoe cube, which is a basic shape structure was built with 1:40 scale to the 6m full scale Silsoe cube and a total of 42 pressure taps were installed on its surface. Pressure measurements were performed for up to 40 m/s in unidirectional and shear flow conditions determined by activating the first or the second inlet at a corner of the WDS. Also different positions of the Silsoe cube model were investigated for determining the optimum testing section for the WDS. Results comparison with pressure distribution obtained in a wind tunnel for a similar Silsoe cube dimensions showed that for certain arrangements the WDS induced pressure was similar with the wind tunnel tests. Also for verifying the WDS design concepts, CFD simulations of the flow acting on the Silsoe cube was performed for the same wind speed as well as the same inlet activation conditions. Good agreement was obtained between the pressure measurement recorded in the WDS experimental facility and the CFD simulation modelled with the LES, for the Silsoe cube with the same dimensions.
Key words: Wind-induced pressure, Silsoe cube model, Wind-induced damage simulator, CFD simulation
Panel discussion on Civil/Construction Engineering Curriculum for New Generation
Panel discussion on Civil/Construction Engineering Curriculum for New Generation
Panel discussion on Civil/Construction Engineering Curriculum for New Generation
Planning and scheduling (1)
Enhancing Planning, Monitoring and Controlling of Road Construction Projects in Egypt Using System Dynamics Methodology
Nabil Amer, Ahmed Okasha, Amir Arafa
Dr. Nabil Amer, Arab Academy for Science and Technology, Cairo, Egypt (Presenter) Mr. Ahmed Okasha, Military Technical College Dr. Amir Arafa, Administrative control authority
In this research, system dynamics methodology is applied to model road construction project in Egypt and represents the effect of changes in time schedule by application of VENSIM software. System dynamics uses stocks, flows, internal feedback loops, table functions and time delay to understand the nonlinear behavior of complex systems over time. It aims to help project managers taking decisions in the highly dynamic environment and assess the performance of project. Also, help minimizing the changes impacts on projects. The introduced model consists of subsystems interacting with each other. Each sub-system contains other small cycles. Factors and cycles integrate with each other to show the project behavior. Also, this model takes into account the effects of schedule pressure, morale, communication congestion, overtime, and experience on the defect rate and productivity. The model is validated by panel of experts in the construction of roads sector. Also, a questionnaire is used for data gathering to feed the model with values of factors and limitation of variables. The results show that system dynamics is better than traditional techniques in planning and controlling the project performance. Integration of system dynamics with the traditional techniques creates advantages for the project manager. In addition, workload is divided and assigned to different companies to simulate the real world and this division is according to the real project division. This division of workload and required operation capacity will increase the productivity of the project and increase complexity of the project. In total, the productivity increased by average 22.23 % along the whole project with elongation in schedule by 8.3 % to overcome the complexity. Finally, Modeling and simulation using system dynamics enables project manager to powerfully estimate the required operation capacity and number of working crews. Hence, the delays in construction projects could be eliminated by good controlling of project using system dynamics methodology.
Integrated Super-structure and Asphalt Deck Scheduling and Optimization Framework for Bridges
Soliman Abu-Samra, Farzad Ghodoosi , Ashutosh Bagchi, Luis E Amador-Jimenez
Dr. Soliman Abu-Samra, KPMG Canada (Presenter) Dr. Farzad Ghodoosi , Concordia University Dr. Ashutosh Bagchi, Concordia University, Montreal, Canada Dr. Luis E Amador-Jimenez , Concordia University
North America’s bridges are aging and deteriorating. According to the Canada’s infrastructure report, around 40% of the existing bridges are in fair and below condition state, which increases their risk of failure and requires further attention. Furthermore, Canada’s infrastructure deficit is estimated between $110 billion to $270 billion and is annually increasing by $2 billion. Given the tight municipal operating budgets coupled with the pressure of maintaining an acceptable level of service, efficient utilization of the maintenance expenditures is becoming of paramount important not only for bridges, but for all the deteriorating assets. Even though, several scholars developed bridge management systems to schedule the maintenance of the bridge concrete deck. Yet, scholars have not considered the spatial proximity between the concrete structure and the asphalt surface. In the lights of those issues, this paper proposes an integrated bridge super-structure and asphalt deck scheduling and optimization framework to ensure proper expenditures utilization, while maintaining the super-structure condition and asphalt level of service. The framework revolves through five core models: (1) bridges’ inventory that contains information about the bridge components, condition state, etc., (2) condition deterioration and future prediction model that simulates the super-structure deterioration across the planning horizon; (3) level of service model that calculates the degradation of the asphalt, represented by the international roughness index; (4) bridge super-structure assessment model that computes a bridges’ super-structure combined index for both the concrete deck’s condition and the asphalt’s level of service; and (5) optimization model that relies on evolutionary algorithms and integer programming using genetic algorithms optimization engine to schedule the corridor interventions across the planning horizon. To demonstrate the framework’s functionality, it will be applied to a bridge across 50 years planning horizon. The results resulted in an extension of 45 years in the service life as opposed to the no repair scenario. The bridge superstructure experienced three major rehabilitation and three minor repairs for the concrete superstructure. The age of the bridge superstructure was 78 years, which is 3 years more than the expected design life according to the code. Furthermore, it resulted in an average IRI of 140 in/mi. For the costs, the EUAC of the structural actions was $18,175. However, the EUAC of the asphalt deck IRI enhancement actions was $7,765, which is 40% of the structural actions. The overall EUAC of the combined superstructure was $25,940.
RESILEINCE PREPAREDNESS-BASED OPTIMIZATION FRAMEWORK FOR WATER AND COMBINED SEWER PIPES: TOWN OF KINDERSLEY
Soliman Abu-Samra, Luis E Amador-Jimenez
Dr. Soliman Abu-Samra, KPMG Canada (Presenter) Dr. Luis E Amador-Jimenez , Concordia University
North America’s infrastructure is at risk. Water and combined sewer and stormwater systems, representing an important part of the cities’ urban infrastructure, are in dire condition state. According to the latest Canadian Infrastructure report card, one-third of the pipes are in fair condition state and below, which requires further attention. Furthermore, more than half of the linear stormwater assets are facing the risk of overflooding due to the increased flow demand/capacity ratio. Even though some scholars developed management systems for pipes to optimize the maintenance and replacement and improve network condition, they ignored the growing effect of urban growth and climate change (i.e. intense and frequent rainfall cause flooding) on the pipes’ deterioration. Accordingly, this paper proposes a scheduling and optimization framework that optimizes the pipes’ replacement decisions to increase their resiliency while considering the annual expenditures, urban growth and its’ future impact on the demand. The framework revolves through five core models: (1) urban and climate change models that simulates the impact of the urban growth and climate change on water and combined sewer pipes; (2) capacity performance model that predicts the future flow demand-capacity ratios based on the estimated population growth, land use changes, and climate change; (3) pipes’ deterioration model that calculates the pipes’ condition across their service life; (4) financial model that computes the life-cycle costs; and (5) multi-objective optimization model that schedules the replacement decisions to minimize the network’s demand-capacity ratio and maximize its condition, while respecting the available budget. The system was applied to the water and combined sewer and stormwater network of Kindersley town, Saskatchewan, Canada. The results showed an optimal intervention schedule with a total of 500 intervention actions across the 25 years planning horizon. Furthermore, it showed an EUAC of $1.7 million and an average condition state of 69% with resilience preparedness of 59% for both networks at the end of the planning horizon. In conclusion, the pipes’ resiliency to flooding could be drastically improved while minimizing the life-cycle costs through maintaining acceptable pipes’ condition states and demand-capacity ratios, identifying condition/capacity deficient pipes, and taking prompt recovery measures.
USING LEAN CONSTRUCTION TOOLS AND 4D MODELLING FOR EQUIPMENT WORKSPACE PLANNING
Charles Igwe, Amin Hammad, Fuzhan Nasiri
Mr. Charles Igwe, Concordia University (Presenter) Dr. Amin Hammad Dr. Fuzhan Nasiri, Concordia University
Transportation developments are shifting from the construction of new highways to the reconstruction of existing ones. The reconstruction of elevated urban highways requires the use of heavy construction equipment, and therefore, planning the equipment workspace becomes very important to ensure that there are no delays to the project completion arising from spatio-temporal conflicts. A number of studies with different perspectives have been carried out to describe the gains of using 4D models in workspace management. However, none of them has considered the effects of the limited usable space in the reconstruction of elevated urban highways. Moreover, the requirements for multiple levels of detail (LOD) in scheduling large and complex projects present a new challenge. To counter these challenges, considerable amount of time is required to ensure that the LOD of the plan is sufficient to account for the following: (1) micro-scheduling of heavy equipment typically used in these type of operations, (2) and (2) producing a 4D model with a sufficient LOD to accommodate daily work plans. The purpose of this paper is to present a research initiative that involves the development of a detailed model for equipment workspace planning by integrating the last planner system with a 4D model with multiple LOD. The development of this 4D model can help detect and resolve spatiotemporal conflicts, reduce the time waste associated with urban highway projects subject to space constraints, improve the reliability of the planning process and increase safety on construction sites. The research method is described, and a case study is developed to demonstrate the feasibility of the proposed method
Planning and scheduling (2)
Application of improving traditional push planning with last planner principles
Mahmoud Hasaballah, Mona Abouhamad, Moheeb El Said
Mr. Mahmoud Hasaballah, Cairo University (Presenter) Dr. Mona Abouhamad, Cairo University Dr. Moheeb El Said
Construction industry is considered one of the major and valuable industries for the economic development and growth in Egypt. An estimated 45% of the funds allocated for the national development plans in Egypt since 1981 were allocated to the construction sector and has been growing 20 % annually since 1980s. Having time and cost overruns is inevitable for project parties. Several Egyptian studies pointed at the planning process and lack coordination as being the main factor of these delays. Improvements to traditional planning were attempted by adopting philosophies like Theory of constrains, action theory, and lean philosophy benefiting from the development in the knowledge of production management in the manufacturing industry. This research utilizes the last planner system (LPS) based on lean construction principles developed by Ballard and Howell. The paper demonstrates two case studies in where Last Planner System is implemented on the construction of two identical steam turbines in parallel. The two projects were constructed by two different teams where the scope was the erection of the identical steam turbines. The Last planner system was attempted by the project controls team of the main contractor of the project, system was established in the 1st case study being constructed through self-execution by the main contractor, while the system failed to be implemented in the 2nd case study constructed by a subcontractor team. The LPS performance metrics for the second case study were observed to be compared to the first case, the primary results from implementing the two cases include benefits gained, barriers of implementation observed, and comparison of results of implementation. LPS allowed for a more collaborative planning approach, it applies a system of close coordination with the people responsible for executing the plan, allowing them to discuss the plan and perform collaborative constrain analysis and progressively learn from the reasons of non-completion. The research highlights the various challenges in the application of the Last Planner System in the Egyptian Market with degrees of success, feasibility of implementation and lessons learnt.
Concurrent Delays: Comparison among Forensic Analysis Recommended Practices
Moneer Bhih, Tarek Hegazy
Mr. Moneer Bhih, University of Waterloo (Presenter) Dr. Tarek Hegazy, University of Waterloo
Construction projects usually operate in dynamic multi-party constrained environments that frequently cause schedule delays, cost overruns, and disputes among parties. To mitigate construction disputes and fairly apportion delay responsibilities among project parties, forensic schedule analysis becomes necessary. Among the available schedule analysis techniques, two techniques have been widely used by researchers and practitioners to assess delay responsibilities: But-For; and Windows Analysis. Both techniques are considered acceptable tools by courts and arbitration boards. However, several improvements have been introduced to both techniques in literature and in the various forensic analysis standards, each with different assumptions. The different methods vary in their use of a single versus multiple windows of analysis. More importantly, the adoption of either the literal or functional theory, for the concurrent delays, may affect the analysis results. The literal one is a strict perspective that requires true concurrency so that the delay-causing events are happening simultaneously, while the functional theory represents the practical and more flexible perspective that consider project delays concurrent even if the causing events occur in different, but close, time periods. Based on their varying assumptions, the delay analysis results and limitations vary among the various methods in the recommended forensic analysis guides. For example, due to the single window implementation of But-For analysis, it is unable to account for the critical path fluctuations within the window or identify the true concurrency. Windows analysis, on the other hand, produces different results when using different window sizes. In windows analysis, however, calculation errors often occur when the progress events of a single day lead to multiple days of project delays. The allocation of responsibility in this case can be complex, particularly when acceleration by one party is involved. The disparity among the methods and the analysis standards creates confusion and less trust in delay analysis techniques, contributing to escalating disputes and difficulty in assessing time extensions and cost compensations. This research aims at clarifying the misconceptions in the use of the various delay analysis methods, compares among the various forensic analysis standards, and examines the impact of the various assumptions on the analysis results. Accordingly, the paper provides guidelines towards accurate and equitable forensic analysis for both researchers and practitioners.
Construction engineering and inspection (CE&I) costs in the Texas Department of Transportation
Julie Faure, Kasey Faust, Nabeel Khwaja, William O'Brien, William Hale, Lauryn Spearing
Mrs. Julie Faure, The University of Texas at Austin (Presenter) Dr. Kasey Faust, The University of Texas at Austin Mr. Nabeel Khwaja, Center for Transportation Research at The University of Texas at Austin William O'Brien Mr. William Hale Mrs. Lauryn Spearing, The University of Texas at Austin
Construction engineering and inspection (CE&I) costs constitute a large portion of a projects’ engineering and procurements costs and a fraction of its construction costs for State Transportation Agencies (STAs) in the United States. Specifically in Texas, CE&I costs comprised between 3.2% and 4.4% of total construction costs every year between 2005 and 2015. Discussions with subject matter experts from the Texas Department of Transportation (TxDOT) indicate that spending too little on CE&I can lead to quality issues whereas too much could lead to inefficient use of limited public resources. Therefore, the management’s desire to identify optimal resource assignment to CE&I functions. This study seeks to provide an overview of CE&I costs spent by TxDOT between 2001 and 2017 to identify optimal allocation of resources and consequently costs for CE&I functions at the contract level. This study is based on analysis of project-level cost data for 6,577 construction projects conducted during the studied period. Projects were aggregated at the contract level to reduce noise in the dataset, and trends based on project characteristics were identified using Excel. Results indicate that CE&I costs (when expressed as a percentage of construction costs) have an inverse relationship with construction costs, i.e. as the construction contract size increases, the percentage CE&I costs decrease. For instance, the percentage of construction costs used for CE&I on smaller projects with construction costs between $0 and $0.5 million (7.6%) are more than twice as high as this for projects whose construction costs are larger than $10 million (3.1%). In addition, CE&I costs vary based on the project type and comparatively do not vary based on the let date. Noticeably, project types with the highest percentage of construction costs used for CE&I are traffic signals (8.3%), landscape and scenic enhancement (7.8%), and bridge replacement (6.0%). The outcomes of this study can help transportation agencies plan CE&I budgets based on the mix of contract size and project type in their portfolio and identify ways to optimize CE&I resource allocation.
Examining Risk-based Inspection Approaches to Highway Construction Projects
Mamdouh Mohamed, Dan Tran
Mr. Mamdouh Mohamed, University of Kansas Dr. Dan Tran , University of Kansas (Presenter)
State highway agencies traditionally rely on a quality control/quality assurance (QC/QA) to inspect the construction activities. Under this method, the contractor’s QC test results are used as a basis of acceptance. However, this approach does not offset the shortage in resources such as the available number of inspectors, funding, and time restrictions. During the last decade, the emerging state-of-the-practice approach, risk-based inspection, has been adopted in the acceptance of the Q/A construction and testing activities. Several highway agencies have implemented risk-based inspection in their highway construction projects. The risk-based inspection approach typically focuses on a core list of inspection items. This list is prioritized based on criticality of the QA test or inspection activity. This study aims to examine the current practices of the risk-based inspection approaches based on the case-study methodology. Six departments of transportation (DOTs) of California, Florida, Texas, Washington, New York, and Indiana were selected and examined. The results show that acceptance protocols lay in one of two categories, material-based or test-based protocols. The core list of inspection activities varies from agency to agency. The typical criteria affecting the type and number of the core list activities include location, weather condition, and organizational structure. Based on these findings, this study provides a generic approach for the other highway agencies interested in developing risk-based acceptance protocols. This generic approach involves four basic stages, comprehensive list development, core list development, risk assessment, and final protocol. This study enriches the construction body of knowledge and practices by shedding the light on the risk-based inspection in highway construction projects, providing a standard approach to develop a risk-based inspection protocol to offset the shortage in the inspection resources of highway agencies.
SCHEDULE FLEXIBILITY AND COMPRESSION HORIZON: NEW KEY PARAMETERS FOR EFFECTIVE CORRECTIVE ACTIONS
zinab Mohamed, Tarek Hegazy
Mrs. zinab Mohamed, University of Waterloo Dr. Tarek Hegazy, University of Waterloo (Presenter)
Schedule Flexibility and Compression Horizon: New Key Parameters for Effective Corrective Actions
1 University of Waterloo, Canada.
2 Port Said University, Egypt.
Abstract: To meet strict project deadlines, practitioners are frequently faced with situations that require effective corrective actions such as speeding up some construction tasks. As corrective actions are necessary to accommodate the inevitable delays, the ability to do further actions becomes dependent on the capacity of the schedule to accommodate further actions of the schedule. This paper, thus, introduces a new concept “Schedule Flexibility” that refers to the residual capacity of an initial or interim schedule as a function of: (1) the activities’ unused modes of construction; (2) the activities’ unused crashing options; and (3) the activities’ remaining total floats. For practicality, schedule flexibility takes into account the preference in having the corrective action implemented on a short-term or a long-term compression horizon of the project. As such, both the schedule flexibility and the compression horizon become two important parameters that govern corrective action plans. These two parameters are often overlooked in the typical focus on time and cost in schedule compression. A case study project with alternative corrective actions was used to examine the relationship between compression horizon and the schedule flexibility. The case study showed that time, cost, and schedule flexibility can identify the optimum compression plan and its horizon, to correct schedule defaults without exhausting the project’s residual flexibility.
Productivity & Procurement
Defining Effort for Collaborative Project Success
Sean Mulholland, Caroline Clevenger
Mr. Sean Mulholland, University of Colorado Denver (Presenter) Dr. Caroline Clevenger, University of Colorado, USA
Collaborative contracts, such as those used for Integrated Project Delivery, create an expectation of high effort by all project team members. These contracts typically incentivize effort, but a unified definition and understanding of effort is not well understood. Project participants of two collaborative projects were surveyed, and results reveal varied definitions of and, thus, varied expectations of effort from survey respondents. Limited research exists regarding the economic quantification of such subjective factors across project-based activities, and, specifically, there is a gap in research surrounding the quantification of the role that effort plays in project-based work in the construction industry. The objective of this research is to introduce and begin to address a quantifiable and measurable definition of effort for use in collaborative construction projects.
Factors Causing Delay of Materials Delivery in Construction Industry in Eastern Province of Saudi Arabia
Adel Alshibani, Mahmoud Eltourkey, Bahaa Eldin Elmaghraby
Dr. Adel Alshibani, KFUPM (Presenter) Mr. Mahmoud Eltourkey, King Fhad University of Petroleum and Minerals Mr. Bahaa Eldin Elmaghraby
One of the main causes of project schedule delay is the material delivery as it plays an important role in the construction and effects the profitability of all parties involved in the project. This paper introduces study conducted to investigate, identify, and rank the most important factors causing material delivery delays in construction industry in Eastern Province in Saudi Arabia. The methodology applied to achieve the main goals consists of conducting a comprehensive literature review along with interviewing a number of local experts to identify the factors that may cause construction material delivery delays. Through a web-based and paper questionnaire survey, the identified factors were assessed and ranked. Forty-two responses were gathered from experts in different positions in construction industry in the Eastern Province of Saudi Arabia. The responses were gathered from 15 project managers, 21 project engineers, 2 supervisors, 3 suppliers, and a procurement officer. The study found that the most important factors that cause delay of construction material delivery in construction industry in Saudi Arabia are “Late issuance of purchase order (Not following the project plan)” , “Late adoption of the material” , “Delays in approving the shop drawings” , “Late issuance of invoices to the contractor” and “Late issuance of supplier payment”.
The paper is original in the sense that although many researches have been conducted to identify the causes of construction schedule delay, very limited research conducted to identify causes behind delay in construction material delivery. In addition, the areas of knowledge and practice covered in the identified factors were distributed and not available in one source. The identified factors are derived from personal interviews with selected project managers, project engineers, construction supervisors and the others from different positions in project department and from the relevant literature.
Sensitivity Analysis of Construction Schedule Performance Due to Increase in Change Order and Decrease in Labor Productivity
Sharareh Kermanshachi, Behzad Rouhanizadeh
Dr. Sharareh Kermanshachi, University of Texas at Arlington (Presenter) Mr. Behzad Rouhanizadeh, University of Texas at Arlington
In the initial steps of construction projects, the contractors do an effort to predict the construction process and timings as accurate as possible; however, a number of change orders (COs) and corresponding reworks are inevitable. A routine challenge in every project is to quantify the impact of COs on labor productivity which can cause adverse consequences on the cost and schedule of the project if not be measured and controlled appropriately. There are many variables that impact the construction process and the duration of the project. For owners and contractors, it is important to know which variables more critically violate the project process and timing. Therefore, in this study, a sensitivity analysis was performed to identify the variables that more significantly influence the performance of the system and project duration. The analysis was performed for a typical project plan case in order to understand how the plan changes with the changes in variables. Project duration was most sensitive to the project deadline and as the project deadline decreased, the project duration increased. However, this effect was only seen after a certain reduction in the project deadline. An 80% reduction in the project deadline resulted in about a 95% increase in the project duration and an increase in the project deadline had little effect on the project duration. The results of this study can be used by the project planners to avoid exceeding change orders within the projects.
Productivity and workforce issues
EVALUATION OF THE CRITICAL ISSUES THAT IMPACT SUSTAINBLE PERFORMANCE OF SME IN WESTERN CAPE CONSTRUCTION INDUSTRY SOUTH AFRICA
Abstract: A sustainable performance development for SME in the construction industry is a worldwide agenda including the establishment of development policy and stimulating the efficient production processes. Still, SME in developing nations are challenging with unsustainable performance notably in the construction industry, and this is centered on management procedure and financial positions, in addition, unsustainable practices of the SME stakeholders, registration policy in place, and attitude of the personnel working in the SME construction industry, create a wide gap for the research study. Thus, trigger the major reason for the evaluation critical issues that impart unsustainable performance of SME in Western Cape. The methodology used for the investigation of critical issues that impact the unsustainable performance of SME in Western Cape is a mixed methods approach, which includes quantitative and qualitative techniques. Quantitative questionnaires were administered to the stakeholders and construction operators include the project manager, quantity surveyor, government officials and entrepreneurship management instructors. Consequently, data collected were validated through qualitative interview among the entrepreneurship instructors, SME stakeholders, and project managers, in order to establish the aim and objectives of the study. The critical issues discovered impact unsustainable performances of SME are as follows; inadequate access to a financial scheme, lack of the necessary collateral to qualify for a loan, labour productivity, lack of recognition for innovation, since SME contribution to productivity is very low and lack of growth objectives serves as a hindrance for development. However, the thought given to the implementation of this identified issues at the inception of SME formation by the stakeholders will enhance the performance and develops innovation for productivity.
Keyword; Evaluation, Performance, SME, Stakeholders and Unsustainable
Framework to Establish the Relationship Between Factors Influencing Construction Productivity Using Fuzzy Interpretive Structural Modeling
Yisshak Gebretekle, Nima Gerami Seresht, Aminah Robinson Fayek
Mr. Yisshak Gebretekle, University of Alberta (Presenter) Dr. Nima Gerami Seresht, University of Alberta Dr. Aminah Robinson Fayek, University of Alberta
The productivity of construction projects is affected both directly and indirectly by numerous factors that range from the micro level (i.e., activity, crew, and project levels) to the macro level (organizational, provincial, national, and global levels). Extensive lists of the factors that influence construction productivity have been developed in previous research, and these influencing factors have also been used to analyze and predict productivity at the activity level or project level. The predictive models developed for construction productivity commonly map a set of inputs (i.e., influencing factors) to construction productivity, but they ignore the interrelationships between different influencing factors. In reality, however, construction systems (e.g., construction projects or construction activities) act as complex systems involving numerous interactions between the different factors that influence their productivity. In other words, the factors that influence construction productivity are rarely independent of each other, and changes in certain factors may cause changes in other factors. Despite the extensive research that has been conducted on identifying the factors influencing construction productivity, there is still a lack of research on the development of a structured approach for identifying the interactions between these influencing factors. Interpretive structural modeling (ISM) is an appropriate technique for identifying the interrelationships between the different factors of a multi-dimensional dataset; however, in this case, the application of the ISM technique poses specific challenges because of the uncertainties associated with factors influencing construction productivity. In this paper, therefore, fuzzy logic is hybridized with the ISM technique in order to develop a systematic approach for identifying the interrelationships between the different factors influencing construction productivity. In order to achieve the research objective, the factors that influence construction productivity are first identified through an extensive literature review. Next, the interrelationships between the identified factors are identified using the fuzzy ISM technique and presented Â using a self-interaction matrix. The results of this research help both researchers and practitioners by improving the accuracy of construction productivity modeling and analysis, leading to more effective project planning and control and an increase in productivity.
Modeling Labor Productivity in Egypt using Regression Prediction Models
Amr Hegazy, Mona Abouhamad, Hesham Osman
Mr. Amr Hegazy (Presenter) Dr. Mona Abouhamad, Cairo University Dr. Hesham Osman, Cairo University
Labor productivity is considered a critical issue in the construction industry in Egypt due to the lack of unified productivity rates together with the increased number of construction project in the last 10 years. Miscalculation of expected productivity rates and ignoring factors affecting the productivity leads to time and cost overrun leading to profit loss for contractor and project delay for owner, in addition to lost resources. This research develops a productivity prediction model through determining the factors affecting the labor productivity in Egypt and modeling their influence. The research used Activity Sampling method for data collection of daily productivity rates and probable factors affecting the productivity. More than 300 data points were collected for multiple activities, factor affecting the productivity, and their rate of change. Analysis is done using linear and non-linear regression prediction models to identify main driving factors for labor productivity given selected project assumptions. This research is a step towards modeling productivity rates in the Egyptian industry instead of relying on International rates which do not represent the Egyptian environment. The research identifies 31 main factors affecting labor productivity and considers four main factors, namely, number of labors per squared area, weather, overtime and constructed element height. The research concluded that these factors are the driving factors for the labor productivity for the demonstrated case study, accordingly the quantification of these factors during or before the project start is necessary to get a near realistic productivity levels. A case study is presented and the model output is compared against national Egyptian Production Rates, several in-house data for leading Egyptian companies, and different international rates.
Productivity analysis of manual condition assessment for sewer pipes based on CCTV monitoring
Yuan Chen, Xianfei Yin, Qin Zhang, Ahmed Bouferguene, Hamid Zaman, Mohamed Al-Hussein
Ms. Yuan Chen, University of Alberta (Presenter) Mr. Xianfei Yin Mrs. Qin Zhang Mr. Ahmed Bouferguene, University of Alberta, Campus Saint-Jean Dr. Hamid Zaman, City of Edmonton, OPERATIONAL SERVICES Dr. Mohamed Al-Hussein, University of Alberta
Closed-circuit television (CCTV) monitoring has been widely employed in North America to assess the structural integrity of sewer pipes. This operation is usually conducted in two sequential phases. The first consists of sending operators to collect videos of sections of pipes using remotely controlled robots equipped with specialized television cameras. In the second phase, the data collected in the field is delivered to the analysis facility where technologists trained in defect classification can examine the video footage. Surprisingly, in many municipalities the video-based assessment of the sewer pipes is conducted manually which is time-consuming and at times demotivating since while very important this diagnosis can be utterly boring. Hence, the duration of condition assessment for sewer pipes is diverse and influenced by multiple factors. Therefore, this paper conducts an assessment productivity analysis model using statistical regression methods in order to investigate the specific factors influencing the duration of manual condition assessment for sewer pipes based on CCTV monitoring. Finally, the proposed method is applied to the case of the City of Edmonton, Canada in order to facilitate productivity improvement for manual condition assessment and human resource allocation.Â
Workforce Resiliency for Careers at Public Transportation Agencies
Kristal Metro, Julia HernÃ¡ndez, Christofer Harper, Susan M. Bogus
Ms. Kristal Metro, University of New Mexico (Presenter) Ms. Julia Hernández Dr. Christofer Harper, Colorado State University Dr. Susan M. Bogus, University of New Mexico
Many employees in state transportation agencies are nearing or entering retirement eligibility, which means that public transportation agencies must focus on recruitment and retention to maintain workforce resiliency. This study addresses potential critical staffing shortages for state departments of transportation (DOTs) located within the United States Department of Transportation Region 6 States (Arkansas, Louisiana, New Mexico, Oklahoma, and Texas) by determining effective methods to address recruitment and retention issues and ensure a resilient workforce. A comprehensive review of the current state of practice within Region 6 DOTs was undertaken with this study. Human resource documents, reports, and training materials were gathered from DOTs as well as interviews with Region 6 DOT human resources staff. These findings were used to assemble a comprehensive survey questionnaire to be distributed to current Region 6 DOT employees. A total of 1,109 employee surveys were collected and reviewed to develop a recommended list of best practices for recruiting and retaining public transportation agency employees. The list of best practices includes increased social media presence, quantification of overall benefit packages, implementation of flexible work schedules and telecommuting, clarification and restructuring of the promotions and incentives process, and increased communication and feedback between staff and management.
Project management (1)
A Study of the U.S. Roofing Industry and its Workforce
Aslihan Karatas, Nathan Staple
Dr. Aslihan Karatas, Lawrence Technological University (Presenter) Mr. Nathan Staple, Lawrence Technological University
Roofing industry is growing fast-paced as the US economy continues to propel forward. Majority of these roofing contractors (i.e., 75 percent) anticipate increase in their revenue next several years. This growth, however, will be expected to bring along industry’s biggest challenge; finding qualified workers. Therefore, there is an emerging need of a statistical analysis on real workforce data to understand of the unique challenges, trends and emerging issues of roofing industry. In order to address this need, this research study focuses on data analysis that investigates a detailed description of the roofing industry workforce, gathers employment and demographic information, geographic location, generational challenges, and types of operations on the roofing workforce. This analysis will guide decisions by the roofing contractors, associations and its members to make informed critical and strategic decisions for roofing industry.
Detecting Top-down Cracks in In-Service Flexible Pavements
Nirmal Dhakal, Mostafa Elseifi, Mohammad Bashar
Mr. Nirmal Dhakal Dr. Mostafa Elseifi, Louisiana State University (Presenter) Mr. Mohammad Bashar
The objective of this study was to establish guidelines to identify top-down cracking in flexible pavements using digital image processing and the characteristics of these cracks. Past studies indicated that the time after construction of the pavement, and location of the cracks are key parameters to identify top-down cracking. The cracks were reported to appear on the wheel path or at the outer edge of the wheel path typically within 3 to 8 years of construction. In-service pavement sections were selected for further analysis based on the parameters identified from the literature and computer-vision techniques were employed on the pavement images to investigate the geometric characteristics of these cracks. Based on the results of the analysis, the average crack width was observed to be 3 to 7 mm; the crack width was found to be 3 to 5 mm in the literature. With respect to the orientation of the crack, the cracks segments were mostly longitudinal with a typical deviation of 20 degrees. The orientation and intensity characteristics of top-down cracks were found as useful features in crack identification.
Impacts of replacing a four-phase signal intersection with a diamond interchange of a selected corridor in Dhaka city using Microscopic simulation
Sadia Nowroz Munia
As most of the existing intersections in Dhaka city have already exceeded the capacity, we need to find alternative solution to minimize the losses in traffic jam. A proper traffic impact study needs to be conducted in order to know whether the alternative solution will mitigate the chronic congestion problem or not. A signalized intersection in Dhaka city, having diverse traffic and geometric characteristics is taken as our study area and data were gathered to calibrate and validate the model of that intersection created in microscopic simulation software VISSIM. After that, this study applies alternative option to the existing condition with the help of VISSIM. As an alternative solution, diamond interchange is used in this study. Diamond interchange uses less space than most types of freeway interchange and avoids traffic signal, which causes hours of operational delay. This research will look at reconstructing current four-phase non-lane based intersection in Dhaka city into a diamond interchange to see how it will perform to cope up with the current peak flow traffic of Dhaka city.
Project management (2)
Decision Support System for Public Private Partnership Investment in Water Projects
Emad Elwakil, Mohamed Hegab
Dr. Emad Elwakil, Purdue University Dr. Mohamed Hegab, California State University , Northridge (Presenter)
Developing positive cash flow projects depends on the inclination and ability of the customers to pay for the offered services. This paper presents an analytical system/method to help Public Private Partnership (PPP) developers and investors to select the region or the area that has the affordability to pay back the loan using Gross National Income (GNI) and access to potable water. A decision making system that includes a model and four investment groups has been developed to categorize the countries into investment groups. The Data used in this paper were collected from 195 countries as well as the percentage of their respective populations that have access to potable water. K-means and Regression Analysis techniques have been used to build the investment groups and the decision making model. The developed system/method has been validate using real data of 40 countries through Average Validity Percent (89.5 %), and R-squared (85.0 %) which, show satisfactory results.
OPTIMIZED ACCELERATION IN LINEAR SCHEDULING
Roghabadi Mohammadjavad, O Moselhi
Mr. Roghabadi Mohammadjavad, Concordia University (Presenter) Dr. O Moselhi, Concordia University
This paper introduces a novel algorithm for optimized acceleration of repetitive projects considering crew work continuity. The model enables planners of this class of projects to identify the optimal/near optimal relaxation time of each activity that leads to minimized project duration and interruption time. The model computations are organized in three modules:(1) a scheduling module designed to generate early and late start schedules, which are utilized to identify the prioritized activities for relaxation; (2) an activity-relaxation total float module that considers the total number of days that the early finish date of each activity (i) in each unit (j) can be relaxed without delaying the early start of its successor activities and without impacting the project duration; (3) an intermediate scheduling module that relaxes each activity in all of its repetitive sections based on its defined activity-relaxation total float to generate a near optimal schedule that simultaneously minimize project duration and work interruptions. An application example of a repetitive construction project is analyzed to demonstrate the capabilities of the developed model in generating a near optimal schedule that account for targeted objectives of project duration and interruptionsâ€™ time.
Progress Facilitation Framework for Construction of Mega Methanol Production Plants
Hassan Beigi, Amirreza Mahpour, Mohammad Mehdi Mortaheb
Mr. Hassan Beigi Mr. Amirreza Mahpour, University of Toronto (Presenter) Dr. Mohammad Mehdi Mortaheb, Sharif University of Technology
In Asallouyeh, Iran among five similar methanol producing plants simultaneously initiated eight years ago only one has been completed so far. It was wondered what could have been done to facilitate the progress of rest. To this end, dimensions and causes of the corresponding lack of progress were elicited through field observations of the incomplete projects and interviews with experts. Analytic hierarchical process (AHP) was applied to construct the research model followed by a questionnaire survey to make pairwise comparisons of the dimensions and the causes. The respondents’ inputs were analyzed by Expert Choice Professional (ECPro) in order to prioritize the items. The study concluded that the political dimension significantly contributed to the status quo of the incomplete projects and “difficult international trading due to political issues” was the most effective cause of keeping the projects behind schedule. Finally, a progress facilitation framework was advanced validity of which was confirmed by the Delphi method.
Project performance tracking and control
A framework for Utilization of Agile in Construction Management
Basma Mohamed, O Moselhi
Ms. Basma Mohamed, Concordia University (Presenter) Dr. O Moselhi, Concordia University
The only thing that does not change in the delivery of constructed facilities is the change itself. Traditional management of construction projects is rather a waterfall-like with a big up-front plan prepared by one department and pushed to the project teams for execution. The truth is that no matter how good that plan is, many unknowns present themselves during the execution which makes the introduction of changes necessary. This requires the project teams to have accurate information about the status of the project at all times and to be empowered to make timely decisions accordingly. In large complex projects, the delay in submitting the progress data to decision makers can lead to problems remaining unresolved related to important issues such as performance deviations and resource allocation. Agile project management has been successful in the software industry, especially when it comes to meeting deadlines and embracing change. This is mainly attributed to the continuous client involvement and the short feedback loops that facilitate early detection of performance deviations arising from unexpected issues. A key principle to be agile is visualizing the current work status physically or virtually by all the stakeholders. Research studies carried out addressing agile in construction were mostly based on either theoretical frameworks, findings from interviews, or application during the design phase only.
In this paper, a brief overview about agile project management is presented along with some examples for its application in the software and construction industries. The paper also introduces a framework to enable construction professionals to fully benefit from the applicable concepts of agile project management. This framework is composed of two automated modules: one for progress tracking employing automated data acquisition technologies and the second one is a web-based collaboration platform that facilitates data sharing and processing among project participants for updating, progress reporting and decision making. It generates visual dashboard type timely progress reports at strategic and tactical levels.Â The limitations and challenges of applying this framework are discussed and more areas are proposed for future work in this emerging research field.
Key Words: Change, Agile Management, Data Acquisition, Progress reporting, Collaboration.
A model for measuring project health in complex construction projects
Ekin Eray, Carl Haas, Derek Rayside
Ms. Ekin Eray, University of Waterloo (Presenter) Dr. Carl Haas, University of Waterloo Dr. Derek Rayside, University of Waterloo
The Project Management Institute’s (PMI) Pulse Report (2013) findings showed that “effective communication to all stakeholders” is the most critical success factor in project management and it is important to all organizations. This includes construction organizations. Large scale construction organizations often undertake several projects concurrently, managing various stakeholders, contractors, subcontractors, and vendors simultaneously. In such a chaotic management environment, project health is directly impacted by any miscommunication, time-overrun on the information requests, or excessive number of design revisions, etc. A healthy project can be defined as a project performing as expected with the project stakeholders functioning towards the project goals as a team. According to the PMI’s Pulse Report (2013), on average two in five projects do not meet the original project goals, and one in five projects are unsuccessful due to ineffective communication. Therefore, a special emphasis needs to be placed on measuring project health between stakeholders. There are traditional quantitative project health measures for construction projects such as schedule and cost variance, but these methods mostly highlight standard project failure symptoms, and don’t have the ability to identify emerging problems between project stakeholders that can cause potential project failure. In 2002, Construction Industry Institute (CII) published “Project Health Indicator (PHI) tool: assessing project health during project execution” to complement traditional measures and to help project managers to get a clearer understanding of the signs of an unhealthy project. Although CII PHI tool brings a new perspective on identifying unhealthy projects, it is based on qualitative assessments of projects managers for 43 leading indicators. In this conference paper, a model for measuring project health between project stakeholders with quantitative indicators that can be applied to a wide range of construction projects, and that can be measured by information management system data such as Interface Management, Request for Information, and Change Management, etc. is presented. The outline of this conference paper is as follows; first, 12 project health indicators are selected from the literature. Second, the weight of each selected indicator is calculated. Third, the required data and calculation method for each indicator is explained. Lastly, project health between two stakeholders of a case project is calculated for two different time frames in the design phase to compare the results using the presented model.
An Extensive Content Analysis of Constructability for Transportation Projects
Adi Al-Smadi, Dan Tran
Mr. Adi Al-Smadi, The University of Kansas Dr. Dan Tran , University of Kansas (Presenter)
An Extensive Content Analysis of Constructability for Transportation Projects
Adi SMADI1 and Dan TRAN2
1Graduate Research Assistant, Department of Civil, Environmental, and Architectural Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, Kansas 66045; email: firstname.lastname@example.org
2 Assistant Professor, Department of Civil, Environmental, and Architectural Engineering, University of Kansas, 1530 W. 15th Street, Lawrence, Kansas 66045; email: email@example.com
Constructability is considered as an effective management tool to optimize project development and meet its objectives. Implementing constructability aims at integrating construction knowledge, resources, technology, and experience into the engineering and design phases of construction projects. Constructability if applied properly can optimize the quality of design plans, cost and schedule estimates, and the utilized construction methods. Many researchers and industry practitioners have investigated constructability over the past decades. However, no efforts have been conducted to analyze the content of constructability-related literature in regards to transportation projects. To address this knowledge gap, this paper intends to analyze previous research efforts as well as industry practitioners’ efforts regarding constructability implementation across transportation projects. The authors collected and analyzed the content of 191 documents related to constructability implementation in transportation projects in the last 30 years. These documents include both journal articles and technical reports. The typical journals were Journal of Construction Engineering and Management, Journal of the transportation Research Board, Automation in Construction, Journal of Performance of Constructed Facilities, Journal of Management in Engineering, Engineering, Construction and Architectural Management Journal, and Journal of Computing in Civil Engineering. The technical reports were mainly from the Federal Highway Administration (FHWA), Construction Industry Institute (CII), and various state Departments of Transportation (DOTs) across the U.S. The content analysis results provide a comprehensive set of trends in constructability, benefits and barriers, and recommendations to enhance constructability implementation. This study contributes to both construction body of knowledge and practices by synthesizing essential issues in implementation of constructability in transportation projects.
Comparing technologies for monitoring the work site occupation for building projects
Stéphane Morin Pépin, Adel Francis
Mr. Stéphane Morin Pépin, École de Technologie Supérieure (Presenter) Dr. Adel Francis, ETS
The use of emerging technologies in the construction industry has the potential to help managers and contractors track the work progress of construction sites. Combined with scheduling methods based on space planning, these technologies could help the stabilization of workflows, ensure better use of available space, a smoother flow of traffic and a reduction of conflicts on construction sites. The purpose is to optimize construction operations and to improve the stagnant productivity in this industry. Technologies such as 360o pictures and videos, laser scans, photogrammetry, LiDAR, barcodes, RFID and augmented reality could have a significant impact in achieving these goals. The purpose of this paper is to study and evaluate the existing technologies and their usefulness for optimizing the occupancy rate on construction sites. Following analyses based on case studies, six evaluation criteria were retained: mobility and portability of systems, the impact of the interventions on work, the speed of the measurements, the quality of the obtained results, the ease of extracting information from the data collected, and the maturity levels of these technologies. Finally, an analysis and ranking are presented in order to measure the suitability of these technologies based on the predefined evaluation criteria.
Cost Growth of Heavy Industrial Construction Projects in Alberta
Danny Haines, Farnaz Sadeghpour, George Jergeas
Mr. Danny Haines, University of Calgary (Presenter) Dr. Farnaz Sadeghpour, University of Calgary Dr. George Jergeas , University of Calgary
Capital investment on heavy industrial construction projects in Alberta is expected to exceed $380 billion in the period of 2017 – 2027. However, companies make these investments in an environment that is subject to some of the largest cost overruns when compared to similar projects in other parts of the world. This cost growth significantly reduces incentives for further investment in the industry and therefore negatively impacts the economy of Alberta. Thus, considering the large size of cost growth in Alberta, and the significant contribution of this sector to the economy of Canada, it is important to identify the factors contributing to this cost growth so that mitigating actions can be taken. A number of factors contributing to cost growth on projects have been examined in the literature, however these studies are not conducted to identify those specifically applicable to the heavy industrial construction sector in Alberta. The objective of this study is to determine which factors disproportionately influence cost growth on heavy industrial construction projects in Alberta. This will allow companies to focus their attention on specific areas and factors to best reduce their risk of cost growth. The study is conducted in partnership with the Construction Industry Institute (CII) and the Construction Owners Association of Alberta (COAA) and uses information on 1,270 projects from Alberta and around the world. This study investigates and quantifies the impact of these factors identified in the literature on cost growth of projects using statistical analysis. Statistically significant differences in project behaviours between Alberta and the rest of the world are determined using inferential statistics such as ANOVA, T-Tests and Pearson correlation coefficients. The results of this analysis demonstrated clearly that projects in Alberta do behave differently than those around the world. This provides guidance for ways in which heavy industrial construction projects in Alberta can be more effectively managed to help reduce cost growth. Lower cost growth that could be achieved by implementing the recommendations suggested by this study could lead to greater cost competitiveness of heavy industrial projects in Alberta. In turn, this could lead to increased investment in the Alberta economy.
Post Occupancy Evaluation of Affordable Housing in the USA: Toward indicators for sustainable affordable housing
Post Occupancy Evaluation (POE) assesses building performance from the occupants’ perspective by exploring the links between satisfaction levels and users’ response behavior after they have adjusted to the building. It has been used to assess projects from the procurement and pre-design stages through building occupancy. Residents’ satisfaction level could be used to identify short- and long-term problems, designate feasible solutions, and provides an effective indicator to improve the living environment. This paper will use a POE survey to examine the existing situation of affordable housing in the USA, and to develop a set of indicators that can lead to create sustainable affordable housing for residents. The survey consists of ten parts that covered different aspects of affordable housing project that are related to the Triple Bottom Line plus One (TBL+1) pillars for sustainability. The survey respondents were asked to rank their level of satisfaction, which results in a natural ordering of very dissatisfied to very satisfied. Being that this variable is ordered, an ordered econometric modeling framework is considered: the ordered probit model. The ordered probit model identifies statistically significant indicators that impact a person’s probability of reporting a specific level of satisfaction. Responses from 72 residents of a family housing at Oregon State University were statistically modeled. The results of the survey analysis revealed a set of sustainable indicators that could be used to create sustainable affordable housing. Recommendations are presented to highlight the importance of those indicators that influence residents’ satisfaction level. In addition, suggestions are made to mitigate the weak points that have led to dissatisfaction among residents and so to improve affordable housing. A set of sustainable indicators based on residents’ point of view will provide a basis for designing sustainable affordable housing that satisfies its users. The results from this study could be used by housing authorities to achieve sustainable affordable housing.
ALKLAI ACTIVATED AGRO-CONCRETE
Diba Ahadzadeh Ghanad, Ahmed Soliman
Ms. Diba Ahadzadeh Ghanad (Presenter) Dr. Ahmed Soliman, Concordia University
Production of construction materials consumes a significant amount of natural resources which has a serious ecological impact. Moreover, cement production has a high carbon dioxide emission leading to environmental concerns. On the other hand, agriculture agriculture industry produces a massive amount of wastes annually which disposing it represents one of the main challenges. Hence, this study investigates the potential of producing alkali activated agro waste concrete (AAAC) “so- called cement-less agro concrete”. Different mixtures were prepared with different percentages of agro waste at rates 0%. 5%,10% and 20% as a volume replacement for sand. In addition, cement based concrete mixtures were also prepared for comparison. Fresh and mechanical properties including slump, water absorption, compressive and tensile strengths and modulus of elasticity were evaluated for all mixtures. Results showed a high potential to produce AAAC with adequate performance. The reduction in alkali activated system was low than that at cement-based system.
Experimental Study on The Mechanical Properties of Recycled Aggregate Concrete Using Crumb Rubber and Polypropylene Fiber
Md. Shahjalal, F M Zahid Hossain, Kamrul Islam, M. Tiznobaik, Shahria Alam
Mr. Md. Shahjalal, MIST Mr. F M Zahid Hossain, University of British Columbia Mr. Kamrul Islam, Ecole Polytechnique de Montreal (Presenter) Mr. M. Tiznobaik, University of Manitoba Dr. Shahria Alam, University of British Columbia
A huge amount of concrete waste is produced every year all over the world due to demolishing old infrastructure. It is a great concern for the disposal of this concrete waste in many part of the world. Using them partly in place of coarse aggregate is one of the methods for constructing sustainable concrete. Comprehensive investigation has been made in this study on the improvement of strength and toughness of concrete having recycle coarse aggregate (RCA) and polypropylene fiber as a partial replacement of natural coarse aggregate (NCA) and cement respectively. Level of RCA replacements are 10% and 30% by weight and fiber are 1% and 2% by volume. Seven different mixes are considered for this research. The results of the mechanical properties are presented in terms of compressive strength, splitting tensile strength and flexural responses of various fiber reinforced concrete (FRC) with RCA in comparison with control mix. In case of fresh properties, slump value decreases with the incremental replacement level of RCA and fiber while on slump value the effect of fiber is more significant than RCA. The result indicates that compressive strength, splitting tensile strength and flexural strength increase with increasing fiber content. FRC shows more toughness and ductility which indicates that concrete containing fiber provides more warning and energy absorption capacity. Finally, this research opens a new horizon of opportunities for utilizing the structural potential of waste materials in construction industries.
INVESTIGATING POTENTIAL IMPLEMENTATION OF DIFFERENT AGRO-WASTES IN CONCRETE
Ahmed Soliman, Diba Ahadzadeh Ghanad
Dr. Ahmed Soliman, Concordia University (Presenter) Ms. Diba Ahadzadeh Ghanad
Concrete is the most widely used construction material.Â However, large volumes of natural resources and raw materials are being consumed in concrete production. This reduces concrete industry sustainability and increase its environmental negative impact. On the other hand, the agriculture sector is facing problems that require more efforts in agro-waste managements. To resolve this problem and benefit from agro-waste, in this study, the potential of using different types of agro-wastes in concrete as a total/partial replacement of aggregate will be evaluated. Three types of agro-wastes, which are categorized based on their fibrosity, fine and coarse, were tested. Full characterization for different agro-waste and corresponding variations in compressive strength, density and microstructure were evaluated. Results showed that the compressive strength is directly affected by the physical properties of the incorporated agro-waste and the type of the binding material. Fibrous agro-wastes exhibited the highest strength with respect to other wastes. Successful use of such agro solid wastes as whole or partial replacement of natural aggregates contributes to energy saving, conservation of natural resources, and a reduction in the cost of construction materials.
Application of Recycled Gypsum Wallboards in Cement Mortar
Sarah Hansen, Pedram Sadeghian
Ms. Sarah Hansen, Dalhousie University (Presenter) Dr. Pedram Sadeghian, Dalhousie University
Gypsum wallboards have been used extensively in the construction industry, however waste gypsum wallboards are often disposed of in landfills instead of being recycled. Landfill sites with large volumes of waste containing gypsum cause leachates with harmful effects on human health and on the environment. Large amounts of carbon dioxide are emitted during the production of cement, so partially replacing cement with recycled gypsum would also help prevent harmful emissions. Gypsum is already known to be added to cement at small percentages in order to reduce the speed of reaction with water, however substantial technical research has not been done using recycled gypsum wallboards containing other materials such as paper, fiber, and paint particles. The primary objective of this research is to use recycled gypsum as a partial replacement for cement in concrete mixtures to introduce a more sustainable solution using recycled materials that is environmentally friendly, while maintaining adequate strength and durability. Several mixtures containing different combinations of cementitious material including Portland cement (50-100%), gypsum (0-40%) and fly ash (0-40%) were mixed with water and aggregates and placed in 50-mm mortar cube molds. After curing in a moist room, the mortar cubes were tested for compressive strength at days 3, 7, 28, and 56. Superplasticizers were used in effort to regulate the consistency of mixtures, as gypsum was found to dehydrate the mixture more than regular cement. Fly ash can increase the workability of concrete mixes, although it is known that large amounts of fly ash require a longer initial setting time and show low early strength. Research showed that mixtures containing only recycled gypsum and Portland cement showed lower compressive strength at all ages, becoming increasingly weak with increased proportions of gypsum. However, combining gypsum and fly ash as partial replacement for cementitious material showed increased compressive strength,
Bond Behavior of Structural Concrete using Recycled Coarse and Fine Aggregates
Charles Rockson, Shahria Alam, Kishoare Tamanna, Ahmad Rteil
Mr. Charles Rockson (Presenter) Dr. Shahria Alam, University of British Columbia Mrs. Kishoare Tamanna, UBC Dr. Ahmad Rteil, The University of British Columbia
Concrete remains the most demanding material in the construction industry and requires the extraction of natural reserves which destabilizes the ecosystem through emissions. The global challenge in the 21st Century of reducing CO2 emissions in the construction industry is paramount in contributing to the sustainability initiatives and development strategy within the industry. One advantage is the use of recycled coarse and fine aggregates which is gaining attention in research and is also being added to international standards. Using recycled aggregates has been limited in proportion and application due to varied engineering reasons (low density, high water absorption, reduced modulus of elasticity, reduced bond strength, etc), and in some instances, eliminating its use for structural elements such as beams, slabs and columns. The bonding properties of using recycled concrete can give credence to expanding the current limitations and application of structural members. In this research the elemental form of beam behaviour (using beam-end specimens based on ASTM A944-2015) to determine the relative bond strength between reinforcements and structural recycled concrete strengths of 30-35MPa is investigated. The beam-end specimens containing 0%, 25%, 50%, 75% and 100% recycled fines and 100% coarse recycled aggregates, were tested to determine the effect of using recycled aggregates. The bond behaviour of 15M&25M bars, with bond lengths of 250mm and a cover of 2*db was investigated in this research. The experimental results are analyzed and discussed in this paper, and its effect in the provision of appropriate bond length is recommended as part of this research. The recommendations in this research can be applied to the use of recycled coarse and fine aggregates in structural elements which can be adopted safely to expand and promote sustainability, and thereby reduce the extraction and consumption of natural aggregates.Â
Experimental Investigation on the Flexural Behavior of Rubberized Concrete Containing Recycled Concrete Aggregate and Polypropylene Fiber
Kishoare Tamanna, M. Tiznobaik, Nemy Banthia, Shahria Alam
Ms. Kishoare Tamanna, The University of British Columbia Okanagan (Presenter) Mr. M. Tiznobaik, University of Manitoba Dr. Nemy Banthia, University of British Columbia Dr. Shahria Alam, University of British Columbia
Owing to the substantially increased demand for natural aggregates in the construction industry, the use of recycled materials as a partial replacement of aggregates in concrete is an environmentally substantial solution. This study in particular focusses on the use of crumb rubber (CR) (0, 10, and 20% by volume) and recycled concrete aggregates (RCA) (0, 50, and 100% by mass) as a partial replacement of natural fine aggregates (NFA) and coarse aggregates (NCA), respectively with an addition of 0.5% polypropylene (PP) fiber by volume of the concrete mix. The flexural behavior of this new concrete with varying combinations of CR, RCA, and PP fiber at different levels was experimentally investigated to determine its modulus of rupture (MOR) and deflection at different loads. Moreover, the post-cracking load-deflection behavior of the PP fiber-reinforced concrete (FRC) beam specimens were captured following the ASTM C1399 standard along with its residual strength measurement under flexure. Results show that, mix RCA100-CR20 with a combination of 100% RCA and 20% CR showed a higher MOR than mix 100-CR10. Also, the PP FRC specimens showed significant post-cracking strength with a maximum residual strength of 2.15 MPa for mix RCA50-CR20-F0.5 with a combination of 50% RCA, 20% CR and 0.5% PP in it.
Recycled Materials in Concrete Applications - Benefits from Waste Free Ontario Act
Solomon Asantey, Amneh Kalloush, Abdurahman Lotfy
Dr. Solomon Asantey, Fanshawe College (Presenter) Ms. Amneh Kalloush, Fanshawe College Dr. Abdurahman Lotfy, Lafarge Canada Inc.
Solomon Asantey, Ph.D., P.Eng.
Fanshawe College, London ON Canada, firstname.lastname@example.org
Amneh Kalloush, M.Eng., P.Eng
Fanshawe College, London ON Canada, email@example.com
Abdurahman Lotfy, Ph.D., P.Eng.
LafargeHolcim Canada Ltd., firstname.lastname@example.org
According to Statistics Canada, the cost of waste management by local governments increased from $1.8 billion in 2004 to $3.2 billion in 2012. The new Ontario provincial government’s Waste Free Ontario Act 1 (WFOA) aims to shift responsibility and cost of recycling programs and materials from the communities and municipalities to manufacturers of waste products. This will potentially motivate manufacturers to find alternative uses for the 4.9 million tonnes of waste generated in Ontario per year. One potential alternative is to reuse post-consumer products in the manufacture of concrete products and cement. Current research focusses on making concrete “greener” by replacing its traditional components with environmentally advantageous alternatives.
The goal of this study is two-fold. First, a survey summary of waste materials potentially useful in concrete production that will be impacted by the Act (WFOA), is presented. Second, a summary and literature review is presented of the five most important waste materials impacted by the WFOA, which have been identified as useful in cement and concrete production.
These five waste materials are glass, polystyrene, polyethylene terephthalate (PET), waste paint and waste tires. A detailed literature review of current concrete research done on these five materials is presented. Data analysed on volume of waste generated versus volume diverted indicate that waste tires result in 109% volume diverted (more than 100% because of previous stockpiling). Thus, of the five recyclable materials, waste tires has the most practical application in the concrete production and construction industry in general.
It is proposed that further research be done to investigate the combination of some of these materials in concrete production. For example, waste rubber and latex paints, with the proper ratios, could be used in roadwork applications for weather resistant, sound absorbing road surfaces.
Keywords: Waste Free Ontario Act, waste materials, concrete, tires, paint, glass, polystyrene, PET
Shrinkage and Expansion of Glass Aggregate Cement Mortar
Karla Gorospe, Emad Booya, Adeyemi Adesina, Sreekanta Das
Ms. Karla Gorospe, University of Windsor Dr. Emad Booya, University of Windsor Mr. Adeyemi Adesina, University of Windsor Dr. Sreekanta Das, University of Windsor (Presenter)
The use of recycled glass aggregates in concrete materials initiated around the 1970s as a means of controlling the disposal of refuse glass. Many researchers have proven that cementitious materials containing recycled glass is sustainable and feasible; however, since its beginnings, uncertainties in its durability have limited its applications. Thus, this research investigated the durability of glass aggregate cement mortars by evaluating its susceptibility to volumetric changes. Shrinkage and expansion of concrete and cement mortar can cause unwarranted cracks which can affect long-term durability and serviceability. In this study, crushed glass and glass beads were used as aggregate replacements to determine their effects on drying shrinkage and alkali silica reaction expansion. It was found that the type, size, and amount of glass greatly influence shrinkage and expansion of glass aggregate cement mortar specimens. Further, the inherently low absorption capacity of the glass improves dimensional stability and minimizes detrimental shrinkage. Incorporating finer glass particles was also found to reduce the effects of alkali silica reaction expansion.
Addressing cost overruns through drafting construction contract clauses: A risk path modeling approach
Tamima Elbashbishy, Ossama Hosny, Elkhayam Dorra, Ahmed Waly
Ms. Tamima Elbashbishy, The American University in Cairo (Presenter) Dr. Ossama Hosny, AUC Dr. Elkhayam Dorra, American University in Cairo Dr. Ahmed Waly, The American University in Cairo
Whether forced by economic conditions or internal motivations, contractors may choose to minimize their mark-up margins in order to maximize their chances of winning a bid. In such cases, they are often more focused to submit bids with the lowest price possible with less regard to the proper profit or contingency margins needed to execute the project. Such drastic bidding conditions render contractors sensitive towards all types of risks associated with executing a project. This is why it is important for contractors to fully understand intricate risk dynamics for effective and efficient risk management. This paper explores risk identification and classification through the risk path approach as a substitute for the traditional risk source-risk factor approach mostly used in Egypt till this day. An ontology model is developed to illustrate the identified risk path, the interdependent relations amongst its elements, and its effect on projects’ costs overruns. The risk path identified in this paper consists mainly of risk elements and vulnerability factors, where risk elements are project uncertainties categorized according to their places within the risk path while vulnerability factors are project vulnerabilities that determines the extent or capacity to resist or cope with risk elements. Risk elements consist of risk sources, risk events, and risk consequences, while vulnerability factors consist of robustness factors, resistance factors and sensitivity factors. An artificial neural network (ANN) is then constructed based on the information logged in the ontology model, where training and testing cases are retrieved from surveying both the literature and experts in the Egyptian construction field. Simulations are conducted using the ANN algorithm to establish the sensitivity of cost overruns to each of the identified risk elements and vulnerability factors. Following this enhanced understanding of risk elements, their relation, and their effect on cost overruns, the paper identifies and develops contract conditions that effectively address the identified risk elements with the greatest impact on projects’ costs. Such information allows contractors to minimize such costs, thus enabling them to minimize their contingency estimates and, consequently, reduce their bid prices.
Energy and cost impacts of CLT- Cross Laminated Timber tall wood building construction. The case of a 10 storey building in Alberta.
The use of CLT - Cross Laminated Timber engineered wood product in major construction projects has continuously increased over the past decade and the global market for CLT products estimated at 556 Million USD is expected to grow at a15% growth rate over the next decade.
Market growth of CLT can be linked to increased demand for sustainable building materials with a low carbon footprint. Recent and upcoming updates to building code in Canada recognize nizing the wood design and construction beyond low rise residential, and the race to construct taller wood mass buildings like the 18 storey residence at the University of BC will support the growth use and application of CLT.
This paper and presentation will focus on a construction project management approach to using CLT. A 10 storey building design is considered and a 3D model is designed with two alternatives for the superstructure: reinforced concrete and CLT. Three different impact analyses for energy consumption, life cycle and cost of both alternatives are developed, and a value management approach is used to benchmark the two designs.
The presentation will aim to deliver the following learning objectives
Review the trends for CLT construction in Canada and globally
Identify various impacts of CLT in the Construction of a 10 storey building
Apply Value Methodology to support sustainable construction projects
ESTIMATING PRODUCTIVITY FOR LABOR-INTENSIVE TASK: A CASE STUDY
Traditional approach of evaluating the efficiency of labor-intensive construction operations compares actual with historical productivity, which provides only relative efficiency. As every project is unique in nature, it may not be a reliable and accurate practice because productivity cannot be easily judged by the data that was documented a decade or more ago. Therefore, it is necessary to determine the absolute efficiency. The study of the productivity frontier and optimal productivity presents an innovative frontier approach for measuring efficiency of construction operations by comparing actual versus optimal productivity. The productivity frontier is defined as a theoretical maximum production level per unit of time that could be achieved under perfect conditions, whereas optimal productivity is the sustainable highest level of productivity that may be achieved in the field under good management and typical field conditions. Such a new approach determines absolute efficiency by avoiding accumulation of the relative errors that exists in the traditional practice. The productivity frontier is a construct that acts as a benchmark to estimate optimal productivity. This research contributes to the body of knowledge by introducing a dual approach framework to estimate the labor productivity frontier and applying it in a case study on the “sheet metal duct sealing” task. The theoretical highest labor productivity for this task was 6.88 ducts per crew-hours. This research presents a decision-making framework for project managers that will help to improve the productivity level of labor-intensive operations by avoiding or minimizing the impact due to operational inefficiency factors.
Integrating sustainability into project risk management; An application in PPP projects
Beenish Bakhtawar, Muhammad Jamaluddin Thaheem, Husnain Arshad
Ms. Beenish Bakhtawar, CECOS University, Peshawar (Presenter) Dr. Muhammad Jamaluddin Thaheem, National University of Science and Technology Mr. Husnain Arshad
Public private partnership (PPP) has been recognized as a potential model for delivery of sustainable infrastructure. The long-duration and risk-sharing mechanisms of PPP contract provide a unique opportunity for fostering innovation and driving sustainable development. However, effectiveness from these features can be materialized only through effective implementation. In PPP projects, sole reliance on the traditional project management procedures and processes limits scope of decision making to the contract duration and the contracting parties. For more informed decision-making, it is useful to align the management of large infrastructure projects with the core values of sustainability assessment focusing both short- and long-term impacts of the project and the changing project environment during its life cycle. In particular, such limitations in approach result in a rigid treatment of risk during the risk assessment focusing only on the iron-triangle project controls as performance criteria. The integration of sustainability into the project management framework is a relatively new concept. In particular, little work has been done on its integration with project risk management framework (PRM). The existing PRM needs to be improved for inclusion of sustainability considerations for efficient management of complex infrastructure projects, especially PPPs. Thus, a systematic literature review of articles ranging from year 2000-2018 has been carried out to propose a conceptual and methodological framework for inclusion of sustainability with PPP outlined in this study. Three areas of resultant integration are referred as: policy, process, and product. Sustainability assessment at three levels of assessment is proposed as; macro, meso and micro levels. The study has long ranging implications for furthering the understanding of risk-sustainability cause-effect chains (opportunity-threat interaction) for developing a decision-support system for sustainability inclusive risk assessment. Overall, the study presents a novel framework for a budding research line helping decision makers to better explore the opportunities created through sustainability for large infrastructure projects and realize long-term project success.
Risk Management framework for proactive assessment of Power Plant projects in Egypt
Bassem Kassem , Mona Abouhamad, Hesham Osman
Mr. Bassem Kassem , Cairo University (Presenter) Dr. Mona Abouhamad, Cairo University Dr. Hesham Osman, Cairo University
The industrial projects construction process comprises additional high impact risks which occur due to the complex nature of these projects. Therefore, the application of risk management becomes necessary to mitigate the impact of its unique risks. This paper introduces a three-tier framework for industrial project risk identification and classification process with application to power plant construction projects in Egypt. The research introduces a risk management framework for assessing and analyzing risks pertaining to industrial projects, with application to power plants in Egypt. The framework covers the different steps in a risk management process, namely; risk identification, analysis, response and, monitoring. The framework comprises a three-tier framework for data collection. The research starts by conducting an extensive literature review to identify risk factors pertaining to industrial projects. The output is further enhanced using feedback from expert using different data gathering techniques. Probability and impact of identified risk are then deducted from reports and structured interviews. Subsequently, risk scores for different risk types are calculated and used to recommend the expected risk classes, proactive actions to mitigate the risk, and contingency actions to accept the risk. The model is applied to a Power plant construction case study. The calculated risk index is compared against the actual risk index. Case scenarios are also presented for the different actions applied versus the recommended actions based upon the risk class identified. The paper demonstrates the importance of the application of risk management process at the early stages and the practical methods to identify project risks and classes for industrial and power plant projects in Egypt.
Risk Transfer in P3 Infrastructure Projects due to Construction Deficiencies
Venkata Vemana, Smitha Koduru, Chris Gentile
Mr. Venkata Vemana, TransEd Partners (Presenter) Dr. Smitha Koduru, Veracity Engineering & Risk Consulting Services Mr. Chris Gentile, City of Edmonton
Public-Private-Partnership (P3) model for infrastructure projects are bid to be design-build-maintain-finance by the concessionaires. The financial success of P3 infrastructure projects depends on the project performance over its entire service life. In traditional design-build, the role of the contractor is limited to ensuring successful construction within schedule and budget while meeting the contractual and regulatory requirements. In such cases, the focus is to optimize the design and construction elements, while the risk of maintenance costs is borne by the infrastructure owner. When a non-conformity arises, typical design-build approach is to consider the design intent and contractual approval by the clients for addressing such non-conformity. In this case, any risk of service life performance remains with the client or owner once the project is closed and the completion is achieved.
In the case of P3 projects, the role of concessionaire is not only to finance the design-build and maintain for a period of time. Therefore, a successful project should not only meet the budget, schedule and contractual requirements, but also minimize the maintenance costs. Any deficiencies at the design-build stage of the project would have negative implications throughout the project service life, and can affect the overall financial performance and ultimate success of the project. Therefore, it is important to not only consider the design intent for safety and minimization of construction costs, but also consider the implications of any actions on the overall durability. In some cases, infrastructure elements that have to be repaired or replaced during the construction stage must be under a greater scrutiny to prevent the risk transfer from the construction stage to the greater operational costs during the maintenance stage.
It may appear inefficient from the design-build point of view to repair or replace an element instead of accepting it as-is, but from the P3 life-cycle point of view, a better course of action would be to accept the cost and schedule delays during construction to prevent taking on greater financial risks during the service life. In such scenario, the construction quality management is a key element to balance between the construction costs, maintenance costs and schedule delays. This paper presents an innovative approach to construction quality management through an integrate quality management program that would involve design-build contractors, operations-maintenance contractors, owners and concessionaires to review and assess the impact of performance requirements and construction deficiencies on the service life and to identify the sources of risk transfer from the design-build stage. Successful application of the program in a P3 infrastructure project is presented through a case study.
Simulation of const. operations
4D Simulation of Rock Excavation Projects
Michel Guevremont, Amin Hammad
Mr. Michel Guevremont, Hydro-Québec (Presenter) Dr. Amin Hammad
4D simulation is commonly used in building construction projects as part of Building Information Modeling (BIM) processes. Recently, the concepts and methods used in BIM and 4D simulation have been extended to civil infrastructure projects (e.g. roads and bridges) under the umbrella of Civil Information Modeling (CIM). CIM can be further extended to represent the sequence of excavation and mining operations in 4D simulation, where excavation blocks are represented as volumetric parts. The dimensions of the blocks are selected based on the drilling equipment and dynamite capacity while taking into account the sequencing of the crew, safety issues, and the natural slope of the bedrock.
This paper aims to evaluate the applicability of 4D simulation in rock excavation projects to determine the feasibility of the excavation methods and analyse the operational features of the construction site. The developed methodology integrates 3D modeling and visualization techniques with a rock excavation simulation that was validated in an actual construction project. The rock excavation operations that can be evaluated with the 4D simulation include drilling (precut and mass), explosives loading into boreholes, blasting, scaling, anchors installation, rock injection and mocking. The details of loading, hauling and rock explosion operations are not included in the current simulation and will be added in the future. The relevant geological features which influence the spatial distribution of excavation operations (e.g. faults, the quality and type of the rock for the sizing of blocks) are considered in the 3D model. In addition, the site layout is modeled including the original ground level and the ramps made from back-fill or untouched rock. The main challenge of the 4D simulation is sequencing equipment and crews for a feasible schedule without spatio-temporal clashes, while respecting safety considerations (i.e. blast pattern, equipment protection, and distances) and other constraints. The resulting 4D simulation can be used to help the decision making of an integrated team of geologists, engineers and construction managers.
A case study was used to evaluate the proposed method. The developed 4D simulation has a high level of detail (LOD) including 722 parts in the 3D model and a schedule with average task duration of 1.5 days. This LOD is needed for reflecting operational constraints with a predefined list of equipment (excavators and trucks). The 4D simulation has proven helpful by establishing a sequencing strategy where the parts are representing mining blocks.
Considering Activity Conflicts in Tower Cranes Layout Planning using Agent-Based Simulation
Mohamed Marzouk, Ahmed Younes
Dr. Mohamed Marzouk, Cairo University (Presenter) Dr. Ahmed Younes, Cairo University
Tower cranes are considered to be one of the most important equipment in large construction projects. The layout planning of tower cranes that defines the types, the quantities and the