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2024 | Book

Proceedings of the Canadian Society of Civil Engineering Annual Conference 2022

Volume 4

Editors: Rishi Gupta, Min Sun, Svetlana Brzev, M. Shahria Alam, Kelvin Tsun Wai Ng, Jianbing Li, Ashraf El Damatty, Clark Lim

Publisher: Springer Nature Switzerland

Book Series : Lecture Notes in Civil Engineering


About this book

This book comprises the proceedings of the Annual Conference of the Canadian Society of Civil Engineering 2022. The contents of this volume focus on specialty conferences in construction, environmental, hydrotechnical, materials, structures, transportation engineering, etc. This volume will prove a valuable resource for those in academia and industry.

Table of Contents



A Solution for Stacking Multiple Precast Housing Modules During Shipment on a Barge

A modular construction company, Nunafab/Illu, is in the process of building high-quality, durable, and energy-efficient total volumetric precast concrete modular houses in Nunavut. The modules are supposed to be stacked on a barge and shipped from a precast concrete plant in Quebec to Nunavut. The roof of the modules is not flat but rather sloped; therefore, in order to place a module on top of another, a temporary stacking structure (TSS) needs to be placed on the roof of the lower module to make it level. In this study, first, a design for a temporary steel structure that will be placed and secured in between two modules is proposed. A steel truss structure with optimal weight, performance, and constructability built using hollow structural section (HSS) members is proposed to be used. HSS members provide high torsional, compressive, and flexural resistance and can be welded at the connections without much complication. Equally distanced bays, two in the 4.5 m long direction and four bays in the 9 m long direction, are considered. The total mass of the TSS is 3.4 T, which is only 3.4% of the mass of a module. Then the anchor bolts, bolted pin, and roller connection designs are proposed. This is the preliminary design for this TSS and can be modified as the project progresses.

Samira Rizaee, Lloyd Alan, Zhen Lei, Brandon Searle
Effect of Concrete Masonry Unit Web Thickness on the Compressive Strength of Concentrically and Eccentrically Loaded Hollow Masonry Prisms

ASTM C90 and CSA A165 are the governing standards prescribing allowable concrete masonry unit (CMU) geometry in the United States and Canada, respectively. Since 2011, ASTM C90 has allowed a decreased web thickness of 19 mm regardless of CMU size. Conversely, CSA A165 has maintained historically used minimum web thicknesses that increase with CMU size starting at 26 mm for 100 mm nominal sized CMUs. Thinner webs reduce CMU weight and so result in reduced cost and potential for workplace injury along with improved energy efficiency. No experimental work was identified examining the contribution of CMU webs to the compressive strength of masonry. It was hypothesized that a reduction in web thickness could lead to a decrease in masonry strength since hollow masonry prisms tend to fail due to tensile splitting through the webs of the CMUs. An experimental program was therefore conducted to examine the influence of varying CMU web thickness on the compressive strength of prisms under eccentric and concentric loading. CMUs with web thicknesses meeting the minimum requirements of ASTM C90 and CSA A165 were used to construct five-course tall masonry prisms. Additional parameters investigated included CMU size, nominal CMU strength, and knock-out units. Thirty-two series with six replicates in each for a total of 192 five-course tall prisms were tested: 120 were subject to axial concentric loading, and 72 were subject to eccentric loading. Preliminary results show that differences in the development of the strain gradient are not significant for prisms built using 200 mm CMUs and subject to eccentric loading, but that statistically significant differences in the resulting masonry assemblage strength exist when subject to concentric loading.

Olga V. Savkina, Lisa R. Feldman
A Wave-Propagation-Based Approach to Estimate the Depth of Bending Cracks in Steel-Fiber Reinforced Concrete

Estimation of the depth of surface-breaking cracks caused by bending in concrete has crucial importance in order to predict the remaining load capacity of the structural member. In practice, ultrasonic tests are the most common methods to assess the condition of concrete. However, the commercial ultrasound-based methods focus on the estimation of thickness of the structural element rather than the crack depth. The cracks cause dispersion and attenuation in the propagating waves, and thus by monitoring the changes in these wave characteristics, diagnostic indexes correlated with the crack depth can be defined. This paper explains this approach performed on six laboratory-scale steel-fiber reinforced concrete beams (50 × 10 × 10 cm3). Each beam is loaded under the crack-controlled three-point bending test until a specific crack depth is reached. These beams are then subjected to ultrasonic testing to acquire the propagating surface waves. The recorded signals are analyzed by utilizing signal processing techniques, including discrete wavelet transform and frequency-wavenumber analysis in order to obtain the attenuation and dispersion behavior of the surface waves. Finally, these wave characteristics are exploited to extract diagnostic features which estimate the crack depth. Herein, the preliminary results for the crack depth estimation based on these proposed diagnostic indexes are presented.

Ahmet Serhan Kırlangıç
Effect of Fastener Stiffness on Buckling Behaviour of Wooden Built-Up Beams

The present study investigates the lateral-torsional buckling (LTB) behaviour of wood built-up beams formed by individual members of the same depth that are fastened or glued together. The LTB capacity of a built-up beam is primarily affected by the level of composite action achieved between individual plies, which is influenced by the fastener properties and locations. The Canadian wood design standard (CSA O86:19) permits full composite action for built-up beam design but is silent on the types and geometries of fasteners necessary to sustain full composite action. The lack of guidance on this topic is also observed in wood design standards in the U.S. and Europe. Within the above context, the present study aims to quantify the effects of fastener stiffness and spacings on the LTB capacity. Towards this goal, a 3D finite element (FE) model, capable of capturing fastener flexibility and predicting the elastic buckling capacity of built-up beams, is developed. The stiffness of fasteners commonly used to connect the plies of the built-up beam is obtained from literature and used as inputs in the FE model. The results obtained from the FE model indicate that the LTB capacities of built-up beams are sensitive to the fastener lateral stiffness and spacings, although the correlation is not linear. It is anticipated that the outcome of this study will help develop clear design guidelines and detailing for the buckling capacity of built-up beams.

Robabeh Robatmili, Yang Du, Ghasan Doudak
Application of Digital Image Correlation (DIC) Method for Concrete Masonry Prism Testing

Concrete masonry units (CMUs) with knock-out webs are used in masonry construction to accommodate the horizontal reinforcement that provides structural integrity to the elements. Their use reduces structural self-weight, transportation costs, and potentially minimizes workplace injuries. However, the impact of using knock-out web units on the strength of masonry members and resulting failure modes has not been investigated. An experimental program was therefore conducted to investigate the load-resisting mechanism and failure behavior of masonry members constructed using knock-out web units. Accurate measurements of surface deformations and cracking patterns were therefore required. Conventional point-to-point strain measurement methods do not provide adequately detailed information on surface deformations and so cannot be used to describe the behavior of masonry members constructed using knock-out web units. It is also challenging to obtain consistent results using these conventional techniques as they are difficult and time consuming to set up, susceptible to human error, and can be damaged relatively easily. A full-field deformation measurement technique such as digital image correlation (DIC) is a non-contact method and was used to measure the detailed surface deformation and crack patterns of prisms subjected to concentric axial compression. A total of 42 three-course tall prisms were constructed in running bond with face shell mortar bedding in accordance with the provisions in CAN/CSA S304-19. The experimental investigation is ongoing and the results described in this paper suggest that the crack patterns at failure varied with CMU web height.

Nitesh Chhetri, Lisa R. Feldman
Moment Redistribution Limits for Beams with High Strength Steel Reinforcement

CSA Standard A23.3:19 “Design of Concrete Structures” currently requires that the maximum yield strength, used in design calculations, be no larger than 500 MPa. The objective of the research, reported in this paper, is to determine whether the current limits for moment redistribution in continuous flexural members, Clause 9.2.4 of A23.3-19, are appropriate if High Strength Reinforcement is used. Sensitivity analyses were conducted, using SAP-2000, for two-span continuous beams with various quantities of ASTM A615/A615M Grade 100 (690 MPa) and ASTM A706 Grade 60 (420 MPa) steel reinforcement, and concrete strengths of 30 and 70 MPa. Loading cases where the live load was applied simultaneously on either both spans or on one span only were considered. Preliminary results suggest that if a full plastic collapse mechanism is present at failure, the moment redistribution percentage is independent of the grade or quantity of reinforcement. If the failure load is limited by insufficient inelastic rotation capacity at the first plastic hinge, the maximum permitted redistribution must reduce for beams with increasing mechanical reinforcement ratio, ω, values. Although the maximum permissible redistribution percentages are less for beams reinforced with Grade 100 steel than Grade 60 steel, the A23.3-19 provisions remain conservative in the cases investigated.

Sohaib Akbar, F. Michael Bartlett, Maged A. Youssef
Investigating Release-Connection Between Post-tensioned Concrete Slab and Wall

In the construction of post-tensioned concrete slabs, the slab shortening due to concrete shrinkage, creep and post-tensioning compression should be considered in the design of slab-wall connection to minimize the cracking caused by wall restraining effects. Various connection details are used in practice to mitigate the cracking. One Release-Connection involves wrapping the vertical dowel, which connects the slab and wall, with a compressible material. The behavior of this connection has not been investigated in the literature. In this experimental study, the performance of this connection under lateral loading is investigated. Several experiments were performed on full-scale 14-inch thick concrete specimens (typical in post-tensioned transfer slabs) poured over smooth concrete surface separated by a layer of bond breaker. The connecting hooked dowels were wrapped with a one-inch-thick compressible material. Two cases were examined. One with the entire dowels within the slab wrapped, and the other with only the dowel vertical portions wrapped, while the hooks were directly in contact with the concrete. Under seismic actions, the friction between the slab and the wall, which are separated by a bond breaker, is ignored. Furthermore, it is usually assumed that the wrapped dowels do not provide lateral resistance, until the wrapping is fully compressed. For the experiments, in which the surface of base concrete was polished, the friction coefficient was approximately 0.4. This value increased to 0.8 when the surface was hand-troweled. The connection began to resist horizontal force prior to 1ʺ movement. The source of this resistance is concluded to be a combination of the resistance due to densification of the wrapping material, friction between the slab and support, and a complex bending of the dowels. This study investigates and characterizes the lateral load resistance of such connections. The results of this study will help better evaluate the behavior of this type of Release-Connection by providing insight into its response particularly where it is used as a permanent connection. Utilized as a permanent connection, this will considerably reduce the construction time of post-tensioned concrete slabs.

Mohammad Jonaidi, Mehrdad Sasani, Simin Nasseri, George Williams
Experimental Investigation of Single-Story CLT Shear Walls

This paper presents experimental investigations on cross-laminated timber (CLT) shear walls for application in platform-type construction. A total of 8 single shear walls and 19 vertically with plywood splines connected coupled shear walls were tested with nailed hold-downs and shear brackets. The CLT panels were 7-ply 191 mm thick, the hold-downs and shear brackets were installed in different numbers and nails as well as with and without plate washers to create different yielding mechanisms. The shear wall lateral performance was assessed as a function of panel aspect ratios, number, and spacing of hold-downs and brackets, the number of nails in the spline joints, and the level of superimposed gravity loading. The tests showed that the shear wall aspect ratio and the size of the hold-down had a significant influence on the wall performance, while the reduction in hold-down nails and the shear bracket size did not.

Md Shahnewaz, Carla Dickof, Thomas Tannert
Reliability Analysis of Structural Elements with Active Learning Kriging Using a New Learning Function: KO Function

Reliability analysis is frequently used in structural engineering for the calibration of load and resistance factors, safety assessment of complex systems, and reliability-based optimization of structural systems. Crude Monte Carlo simulation (MCS) provides a complete and strong solution compared to other reliability methods since it can solve multimodal and highly nonlinear problems irrespective of the continuity of the limit state and performance functions. The number of crude MCS trials for reliability analysis can be very high which adversely impacts its efficiency, especially for complex limit state functions. Surrogate models were used with MCS to form an efficient and accurate solution for the reliability analysis. Active learning Kriging (AK) MCS is one of the most robust reliability methods that takes the advantage of surrogate modeling to decrease the cost of calculation while utilizing the accuracy of MCS. The key element in AK-MCS is the learning function which determines the degree of accuracy of the reliability results (the probability of failure and the reliability index) and governs the efficiency of the analysis. This paper investigates the validity and performance of a new learning function for AK-MCS reliability analysis, named KO learning function, using two relevant examples. Analysis results indicated that the KO function is a valid learning function for AK-MCS, and it enhances the performance of AK-MCS compared to other learning functions for the studied examples.

Koosha Khorramian, Fadi Oudah
Effect of Random Fields in Stochastic FEM on the Structural Reliability Assessment of Pile Groups in Soil

Stochastic finite element method (SFEM) is used to consider the spatial variability in the material properties of the model components by utilizing random fields (RF). When combined with a robust reliability framework of analysis, SFEM offers significant advantages as compared with conventional deterministic FE analysis, particularly for complex systems with variability in the material properties. SFEM has been used in literature by examining the reliability of pile group foundation in soil by considering the spatial variability of the soil while discarding the variability in the properties of the pile and the pile cap. The objective of this paper is to recommend the minimum number of RFs required to effectively model the resistance of a pile group consisting of 10-m-long four steel piles embedded in loose sand and evaluated at the serviceability limit state (SLS). A limited parametric study of the following cases was conducted: deterministic analysis without RF, SFEM with only soil RFs (friction angle and stiffness), SFEM with soil and pile RFs, and SFEM with soil, pile, and pile cap RFs. Analysis results concluded that discarding the spatially variability in the piles and pile cap has marginal impact on the resistance model at SLS, and thus, SFEM with only considering the variability in soil suffice for the considered cases. The SFEM model with soil RFs was utilized to conduct a crude Monte Carlo simulation (MCS) to evaluate the reliability of the pile group at SLS.

Koosha Khorramian, Abdalla Elhadi Alhashmi, Fadi Oudah
Time-Dependent Reliability Analysis of Degrading Structural Elements Using Stochastic FE and LSTM Learning

Time-dependent reliability assessment of complex structural systems that require finite element (FE) simulation to evaluate the limit state function by means of random fields is computationally demanding. The computational cost is frequently unaffordable unless reliable surrogate models of the performance function are developed. In this research, a novel approach is employed to conduct time-dependent reliability analysis of degrading concrete structures based on long short-term-memory (LSTM) technique and stochastic (S)FE simulation, where the structural material properties are simulated using random fields. LSTM is a neural technique that accounts for the sequence dependence among the input variables, and it is versatile for time series prediction. It is a type of recurrent neural network used in deep learning, and it is proven to be efficient in training for large architectures. The proposed analysis method was used to determine the time-dependent reliability indexes of two examples. The first example was related to a mathematical limit state function with time-independent random variables and time-dependent Gaussian processes. The second example was related to a degrading glass fiber reinforced polymer (GFRP) reinforced concrete beam modeled using SFE. Analysis results indicate the versatility of the proposed framework of analysis and the accuracy of the predicted reliability indexes.

Fadi Oudah, Abdalla Elhadi Alhashmi
Automated Assessment of Municipal Solid Wastes Using a Hybrid Sine Cosine Algorithm-Based Neural Network

Municipal solid waste management has emerged in the recent few years in contemporary built environments due to the rapid increase in population and urbanization. Hence, this research aims at developing a hybrid sine cosine algorithm-based feed-forward artificial neural network model for forecasting waste quantities in Poland. In addition, the developed hybrid model is compared against the classical feed-forward artificial neural network model. The performance evaluation analysis is explored using the indicators of mean bias error, root-mean-squared error, Pearson correlation coefficient, Willmott’s index of agreement, and coefficient of efficiency. Test results illustrated that the developed hybrid feed-forward artificial neural network model trained using sine cosine algorithm significantly outperformed the classical neural network model. It can be argued that the developed model could assist decision-makers in the proper management of growing quantities of municipal solid wastes.

Nehal Elshaboury, Abobakr Al-Sakkaf, Ghasan Alfalah, Eslam Mohammed Abdelkader
Behaviour and Resistance of Glued-Laminated Timber Subjected to Impact Loading

An increase in the exposure of structures to accidental and intentional blast explosions over the last three decades has led to a desire to increase our understanding of blast load effects on structures. High magnitude and short duration loading events, such as blast explosions and impacts, have the potential to generate catastrophic effects on infrastructure and to cause loss of life. Although design provisions for engineered wood products are included in Canada’s current blast design standard, CSA S850, how these structural materials respond to blast and impact loads across a wide range of high strain rates have not been well documented. An experimental programme was carried out to investigate the flexural behaviour of glued-laminated timber (glulam) subjected to impact loading. A total of nine 137 mm × 267 mm × 2500 mm glulam beams were tested under quasi-static and dynamic loading in order to document high strain rate effects and their behaviour under extreme loading conditions. Dynamic testing was conducted using the newly established drop weight impact testing facility at the Royal Military College of Canada, capable of imparting up to 23 kJ of energy onto small to full scale structural elements. Average dynamic increase factors of 1.13 and 1.20 on the maximum resistance and stiffness, respectively, for strain rates between 0.67 and 1.05 s−1 were determined, and characteristic static and dynamic failure modes were documented. This research will contribute to recommended changes to blast design parameters.

Nicole Wight, Christian Viau, Patrick Heffernan
Vibration Performance of Mechanically Laminated Timber Floors

Mass timber panels including cross-laminated timber (CLT), dowel-laminated timber (DLT), and nail-laminated timber (NLT) are largely used as floor slabs in mass timber buildings or hybrid timber buildings. As a lightweight material with a relatively high strength/stiffness to density ratio, mass timber floors are prone to foot-fall induced vibration. Vibration serviceability limit design often governs the maximum allowable span of mass timber floors. In this study, the dynamic properties and vibration performance of DLT floors were investigated. The applicability of the CLT floor vibration design equation in CSA 086-19 to DLT was first verified. The result showed that with rigid supports, the current CLT floor vibration design equation can be used for DLT floors with appropriate elastic stiffness values. Additionally, the acceleration responses of DLT floors under normal human walking with different measurement locations and walking paths were recorded and analyzed. The root-mean-square acceleration data was compared with the acceleration criteria and multiplying factors in ISO 10137, indicating a poor correlation with the result of subjective evaluation.

Chenyue Guo, Zijian Zhao, Jianhui Zhou
Behaviour of Cross-Laminated Timber Slabs Subjected to Fire—A State-Of-The-Art Review

In a new era, full of possibilities for manufacturing large timber sections made of engineered wood, such as cross-laminated timber (CLT), the strength and structural integrity of mass timber sections can be retained for a much longer time in fire. Increased availability of CLT in Canada and its successful use in mass timber construction worldwide have generated interest in its properties and performance when subjected to fire. There are many benefits of using CLT, such as utilizing sustainable and renewable construction materials like wood and the fact that CLT has excellent acoustic, thermal, and seismic performance. However, having a product with a broad portfolio of choices brings many difficulties, specifically in terms of how the number and thickness of the lamellae of a CLT slab can affect its fire performance. This chapter summarizes the most recent research on the behaviour of CLT floor slabs when exposed to fire. The review of the state-of-the-art literature discusses different experimental works examining the change in internal temperatures, char depth and progression, and structural integrity of CLT floor slabs when subjected to fire. The reviewed research studies varied in the scale of testing, test setup, make-up of CLT sections, and wood species utilized. Despite the variances across the different reviewed studies, many of the same conclusions were drawn, providing consistency in the general outcomes. Although experimental testing is the ground truth to verify the fire resistance of construction materials and structural assemblies, fire testing is time-consuming and costly. This demonstrates the need for developing computer models that can accurately simulate the actual behaviour of CLT slabs when subjected to fire. Accordingly, this chapter also discusses recent numerical and modelling attempts to simulate the behaviour of CLT slabs when subjected to standard and natural fire scenarios.

Sarah Barclay, Sam Salem
Experimental Fire Testing of Damaged Glulam Beam Connections Retrofitted with Self-tapping Screws

The main objective of the research study presented in this paper is to investigate the effects of using self-tapping screws (STS) to retrofit damaged glulam beam connections subjected to standard fire. In this experimental study, two full-size glulam beam-end bolted connections with wood-steel-wood connection configuration utilizing two different bolt patterns have been retrofitted using STS after being deliberately damaged through physical testing until failure. In the connection configuration with the first bolt pattern (4BP1), two rows of bolts, each of two bolts, were symmetrically positioned near the top and bottom sides of the beam section. Whereas in the configuration with the second bolt pattern (4BP2), the bottom row of bolts was shifted upward to be located at the mid-height of the beam section to further contribute to the moment-resisting capacity of the connection. Subsequently, the retrofitted connections were experimentally tested at elevated temperatures that followed the CAN/ULC-S101 standard fire time–temperature curve while being loaded to the maximum design load of the weakest undamaged, unreinforced connection configuration. The experimental results of the retrofitted glulam beam connections were compared to those of identical but undamaged, unreinforced connections that were experimentally tested in a prior related study to highlight the influence of STS in strengthening the damaged connections when subjected to fire. Results show that the retrofitted glulam beam connections maintained a minimum of approximately 67% of the fire resistance time of identical but undamaged, unreinforced connections.

Mohamed Hegazi, Sam Salem
Finite Element Modelling of CLT-Concrete Composite Sections Utilizing Wood Screws as Shear Connectors

Mass timber buildings such as those made of glued-laminated timber (glulam) framing systems supporting cross-laminated timber (CLT) floor slabs can be designed to successfully achieve the limit state design requirements for both strength and serviceability. Floor systems in such buildings can even be made more robust and span longer distances by adding a top concrete layer to allow the formation of timber-concrete composite (TCC) floor systems when adequate shear connections are utilized. The primary technique for shear connections in TCC systems is a wide variety of metal connectors, with the self-tapping screws being one of the most used shear connectors. The numerical study presented in this paper aimed to investigate the shear characteristics of CLT-concrete composite sections that utilized wood screws as shear connectors. Three-dimensional finite element (FE) models for CLT-concrete composite sections have been developed using the commercial FE programme ABAQUS. The FE models were validated against the experimental results from a prior related study on TCC sections with concrete age of 28 days. Test specimens had 600 mm × 1000 mm shear interface between the CLT panel and concrete layer, and were experimentally examined under direct shear forces until failure. Details of the constitutive laws adopted for simulating timber and concrete in such TCC sections are addressed. The competency of the damage model implemented to capture the bi-axial stress state of wood material is also discussed. The FE models have an acceptable correlation with the experimental results, with the capability of simulating the slip behaviour between the timber panel and concrete layer.

Javad Tashakori, Sam Salem
Design and Construction of Temporary Works to Facilitate the Construction of Go Rail Tunnel Under the Highway 401 and 409

Toronto Tunnel Partners (TTP), under the contract to Metrolinx, recently completed the construction of two 10 m tall, 8.5 m wide rail tunnels crossing 21 lanes of Highway 401 at the Highway 409 interchange to facilitate the future expansion of the GO transit rail corridor. The tunnels were advanced by use of the Sequential Excavation Method (SEM) and required the use of a pre-support pipe canopy to assist with the ground support above the tunnel crowns. A 26 m × 10 m × 9.8 m deep strutted sheet pile shaft was constructed occupying the full median space between Highway 401 and 409 lanes to facilitate auger boring operation necessary to install this pipe canopy. The shaft also aided in the temporary support to the adjacent existing rail tunnel and bridge wing walls that were partially exposed during construction. The shaft also needed to be designed to allow for pipes to be installed through the load resisting sheet pile walls, and later the unbalanced loading during the tunnel construction. At the tunnel portals, a custom thrust frame was required to allow the contractor to complete auger boring up to 4.5 m above grade and was required to resist a 250-tonne thrust load at this height. Retaining walls and work platforms were also required at the portals to facilitate installation of monitoring equipment and temporary support of equipment on the active railway during short duration closures. This paper will provide a comprehensive overview of the design and installation of the unique temporary structures which helped facilitate the construction of this challenging project.

Prakash Nadesparan, Tyler Lahti, Mary Jane Ferraro
Comparison Between Effects of Current Wind Turbine Design Loads and Downburst Loads

Wind turbines are among the most rapidly increasing technologies for delivering sustainable energy. Good wind sites are usually found in rural regions, where thunderstorms and strong wind events are becoming more frequent and destructive, as a result of climate change. Downbursts are one of these events linked with thunderstorms which occur in a sudden and localized manner. One of the challenges in the analysis and design of wind turbines under downbursts is that, the associated forces acting on the tower and blades depend on the characteristics of the event including its size and location. The review of current design codes for this type of structures shows a lack of procedures for estimating the wind loading on wind turbines due to high intensity wind events, such as downbursts. The wind loads used in those design codes are based on large-scale wind events. In the current study, a comparative study is conducted using the previously developed numerical model, HIW-TUR, on a variety of wind turbines in order to assess the differences between current wind turbine design loads and downburst loads. HIW-TUR accounts for different downburst parameters, such as the size, jet velocity, and the location relative to the wind turbine center, as well as the change in the pitch angle of the blades. An extensive parametric study is conducted considering a large number of downburst configurations and different blade pitch angles. Moments at the tower base and the roots of the blades are obtained under different downburst configurations and are compared with those calculated using the International Electro-Technical Commission IEC 61400-1 [10]. Using the same reference velocity, downburst loads on wind turbines are found to be higher than the design loads, resulting in higher straining actions on the tower and blades.

Mostafa Ramadan Ahmed, Ashraf El Damatty, Kaoshan Dai, Wensheng Lu
Effect of High Intensity Wind Loads on Steel Poles Transmission Lines

The vulnerability of transmission lines to high intensity wind (HIW) loads, such as downbursts and tornadoes, has been realized through several transmission lines failures around the world. Transmission poles are commonly used in urban and suburban high-voltage transmission lines. However, transmission poles can be more vulnerable to HIW loads than lattice transmission towers due to their limited redundancy. The study aims to investigate the sensitivity of steel poles transmission lines to downbursts and tornadoes. The critical load cases are determined by equating the peak straining actions due to HIW loads, to those obtained due to the synoptic wind and ice loads cases. HIW loads cases are calculated using the new provisions recently incorporated in ASCE 74 (2020) guidelines. The results of this study provide the magnitude of HIW loads beyond which the considered transmission poles are not safe, if they were designed to withstand only synoptic wind and ice loads cases without a margin of safety.

Ahmed Shehata, Abdelrahman Ahmed, Ashraf El Damatty
Performance of Timber-Steel Dowel Connections Reinforced with Self-tapping Screws Under Monotonic and Cyclic Loading

The use of mass timber for mid- and high-rise structures has risen dramatically in recent years and is expected to continue to increase given recent changes to the 2020 National Building Code of Canada, which permits mass timber structures up to 12-storeys tall. Critical to the growth of mass timber in Canada is the development of safe and resilient seismic force resisting structural systems (SFRS). One common SFRS used for mass timber structures are braced frames. In mass timber braced frames, the steel connections are relied upon to provide ductility and energy dissipation capacity under earthquake loads. However, the ductility and energy dissipation capacity of steel dowel connections can be limited by the onset of a brittle failure mechanism, (e.g. row shear or group tear-out) prior to significant dowel yielding. To address this challenge, this paper presents experimental results on the structural performance of timber-steel dowelled connections reinforced with self-tapping screws. Twelve connections were tested under monotonic and cyclic loads. The tested connections included two different fastener diameters of 11 and 16 mm, with an internal steel plate, both with and without reinforcing screws designed to prevent brittle shear failure. Experimental results demonstrate that the use of a larger number of smaller fasteners results in higher connection ductility before the onset of brittle row shear failure. Furthermore, results show that reinforcing steel dowel connections with self-tapping screws can significantly increase connection ductility and effectively prevent premature shear failure. Under cyclic loading, tested connections reinforced with self-tapping screws exhibited significant ductility and energy dissipation capacity. Overall, results of this study demonstrate the potential for using self-tapping screws to reinforce steel dowel connections and improve the seismic performance of mass timber braced frames.

Thomas Breijinck, Joshua Woods, Colin MacDougall
Assessment of Current Analysis Methodology of Light-Frame Wood Buildings Under Lateral Loads Using Wood3D

Wood shear walls are the main components used to resist lateral loads in a light-frame wood building (LFWB). In a previous study, a novel simplified model, that accurately predicts the deformations and the straining actions in the shear walls of a LFWB through three-dimensional finite element analysis, was developed. This efficient model implicitly simulated all the components of the shear walls including the sheathings, the studs, and the nails. In this model, the bending and the shear stiffness of the walls are simulated using nonlinear link elements. An extensive database was developed to determine the link properties for all the work configurations. An interface was also developed that is integrated with the commercial software ETABS and the database, allowing an efficient three-dimensional analysis of LFWBs under lateral loads. This numerical package is named “Wood3D”. The software Wood3D can estimate the straining actions in all the components of a LFWB under the combined effects of gravity and lateral loads. In the current study, Wood3D is used to analyze and conduct a design check for an existing LFWS that was designed using the approximate procedure, currently employed in the industry. The results are used to assess the accuracy of this approximate procedure in comparison with the rigorous analysis and design checks conducted using Wood3D. Three models of the existing LFWB are generated using different modeling assumptions. The results from this analysis conclude that the current design method for wood shear walls in the industry is over-conservative.

Aya Risha, Adnan Enajar, Ashraf El Damatty
User-Friendly Time-Dependent Reliability-Based Charts to Evaluate the Structural Safety of RC Wharf Decks Exposed to a Changing Environment

This paper presents a robust time-dependent reliability-based analysis framework to evaluate the service life of steel reinforced concrete (RC) wharf decks subjected to gravity loads and exposed to corrosion and freeze–thaw damage. The effect of climate change on the freeze–thaw damage was considered in the analysis. The robust framework of analysis was utilized to generate a family of user-friendly evaluation charts calibrated for Halifax, Nova Scotia environment. A practical example of utilizing the charts to assess the service life of an existing RC wharf deck was demonstrated. Multiple families of evaluation charts can be generated based on refined knowledge of site-specific parameters across Canada, multiple design standards and load combinations, and wharf importance categories.

Fadi Oudah
Design and Behaviour of Walls Over Compressive Soil Case Study: Repair of the Vergel Bridge in Mexico

Over the years, the construction of mechanically stabilized earth (MSE) structures has been a practical solution in infrastructure projects; the simplicity in installation and economical benefits are well accepted nowadays. Designing and construction of a structure founded on a compressible soil is one of the major challenges in retaining wall projects; MSE wall is not an exception [1]. In cases that large settlements are expected, special considerations shall be taken into account for the design, site preparation, and construction in order to guarantee a sound performance [2]. The MSE walls of the Vergel Bridge in Northern Mexico were founded on a highly compressible ground. The ground improvement solution consisted of a series of pressure grout injection. Further to poor ground problem, an out-of-spec backfill was used as the reinforced fill in the MSE walls in this project. To overcome this problem, a new supporting retaining wall was constructed in front of the existing wall to stabilize it. Other challenges in this project are regarding construction schedule that should have been carried out without shutting down traffic. This paper summarizes and discusses the design approach and construction process in repairing this structure.

Eder Gutierrez Toledo, Gabriel Calatrava
Structural Damage Detection of Steel Corrugated Panels Using Computer Vision and Deep Learning

In recent years, steel corrugated panels have been introduced in Canada to construct long-span and low-rise frameless systems. However, such systems are prone to have critical structural damages such as buckling under extreme loading conditions such as earthquakes. Identification of these damages is crucial for owners to make informed decisions. In recent years, computer vision methods have been successfully developed and applied in structural visual damage detection for different types of structures including concrete, steel, masonry and timber structures, ranging from regional-scale post-disaster collapse identification, to localized applications such as metal surface defects detection, joint damage detection, concrete crack and spalling detection. However, there are almost no attempts in vision-based detection of buckling damage. In this paper, a hierarchical buckling damage detection framework has been proposed for steel structures, which consists of system-level buckling identification, component-level buckling localization. First, global buckling identification is performed on the image of the panels using the convolutional neural networks (CNN)-based classification algorithms. If the panel is identified as buckled, then the YOLOv3-tiny object detection algorithm is applied to localize the damaged area. Extensive monotonic and cyclic laboratory tests have been conducted on the steel corrugated panels, where image and video data are collected for training, validation, and testing of the CNN algorithms. Results indicate that the CNN-based vision methods can achieve high accuracy in detecting and localizing the buckling damage for the steel corrugated panels. Moreover, additional discussion about further investigations of these steel panels is also presented.

Xiao Pan, Soham Vaze, Yifei Xiao, Sina Tavasoli, T. Y. Yang
Aerodynamic Effects of Height-to-Width Aspect Ratio Variation in Tall Buildings—Numerical Study

High winds are considered among the most dangerous natural hazards besides earthquakes to tall buildings. Under high wind, tall buildings experience aerodynamic effects that play a crucial role in determining their principal wind-induced responses. Nowadays, high-rise buildings are often remarkably flexible, low in damping, and light in weight. Thus, they generally exhibit increased susceptibility to wind-induced responses. Consequently, it has become necessary to develop tools to enable structural engineers to determine wind effects on tall buildings with high confidence from structural integrity and serviceability perspectives. In this regard, computational fluid dynamics (CFD) simulation is a suitable option for studying the sensitivity of wind pressure on tall buildings. The numerical study presented in this paper addresses the aerodynamic response of a standard tall building through large eddy simulation (LES) employing the consistent discrete random flow generation technique (CDRFG). Applying the CDRFG technique to generate the inflow boundary conditions allowed an accurate depiction of the turbulence spectra. The aerodynamics behavior has been investigated for four same-height (180 m) tall buildings with different height-to-width ratios (i.e., 6.0, 4.0, 3.6, and 3.0). Based on the outcomes of the numerical study presented in this paper, it has been found that the wind-induced responses obtained from the LES models led to an acceptable estimation of the wind pressure distribution and reactions of the buildings studied in a time-efficient manner.

Sherine Ali
Bearing Capacity of Precast Hollow Core Slabs at Load Bearing Wall–Slab Joint

Precast/prestressed hollow core slabs are commonly used as floor members but may also be used as roof or wall members in many different types of construction projects. Hollow core slab benefits come from their longitudinal voids running through them reducing weight and material costs. However, due to this reduction in material, their bearing capacity under increasingly high loads may be of concern. This is of specific concern at the ends of the simply supported members where load-bearing walls may sit on top of them and transfer the weight of the structure above through the slab into the walls below. An experimental program was conducted to determine the capacity of hollow core slabs under crushing loads at their terminal ends. A regional precast concrete manufacturer has supplied hollow core slabs for this project. A test frame was designed to simulate the desired loading conditions, and the slabs were setup with their ends abutting and 8″ wide bearing area across the connection as they would be in typical design. The effects of multiple variables were tested to determine how they change the strength of the slabs. These included partially filling the cores with concrete, as well as grouting the area between the slabs to varying degrees to simulate field conditions. The capacity and failure mode of these slabs was determined for the different end conditions. These results give the insight into what is required to satisfy loading conditions, which will help to eliminate unnecessary costs and labor time from the production process of these precast elements in cases where additional core fill is not required.

Lucas Marshall, Alan Lloyd, Rebecca Patterson
Lateral Performance of Log Wall with Butt-and-Pass Corner Style

Log houses are an ancient construction technique. The paper presents an ongoing investigation of the structural response of the log wall corner joint system of the Butt-and-Pass style under lateral loads. The finite element model was developed and validated with the experimental results. A parametric study was performed for assessing the effect of penetration length of the logs on the lateral capacity of the log wall specimens. Several models were created with variable penetration lengths ranging from 20 to 70 mm. The study found an inverse relationship between the penetration length and the lateral stiffness. The analyses showed that the lateral load resistance capacity and the initial stiffness change dramatically once the penetration length passes 55 mm. However, the log wall specimens with penetration lengths less than 45 mm showed better resistance to the lateral loads.

Reza Kalantari, Reza Abbasi, Ghazanfarah Hafeez


Lifting and Rigging Study for Precast Volumetric Modular Construction in Nunavut

In this study, a preliminary design of a lifting and rigging system for a modular construction company, Nunafab/Illu was conducted. The company is in the process of building affordable, high-quality, durable and energy-efficient total precast concrete modular houses in Nunavut. The Off-site Construction Research Centre (OCRC) at the University of New Brunswick evaluated lifting and rigging options for the modules and recommended ways to improve the lifting and rigging process. Therefore, first, the weight and centre of gravity (CoG) of the different modules were calculated. While the heaviest module was considered for the design, the CoG location of every module was considered in the calculation of lifting sling lengths. The length and angle of each sling were calculated in such a way to facilitate lifting from the CoG and optimize the load applied on each sling. Then the possibility of different lifting scenarios was evaluated considering the capacities and limitations of the concrete and lifting accessories. The most limiting condition was the strength of concrete and the availably of lifting inserts. Finally, suggestions were made to the company to be able to use more efficient lifting and rigging methods. The first suggestion was reducing the weight of the module in order to use fewer lifting inserts. That will reduce the number of levels of spreader bars, improves the lifting tree assembly process and time, and reduces divergence from the CoG. Second suggestion was designing and manufacturing of a customized lifting frame instead of using a lifting tree.

Samira Rizaee, Alan Lloyd, Zhen Lei, Brandon Searle
The Alcan Pioneer Road and Discovery of Permafrost

During the 1930s, several American and Canadian commissions examined the feasibility of constructing a continuous highway from the population centers of western and central Canada as far as Dawson for the Canadians and to Fairbanks as the desired terminus of the Americans. The scheme lacked political will and sponsorship until Germany attacked the Soviet Union in June 1941 and quickly advanced to the outskirts of Moscow. Soviet emissaries began lobbying their new North American allies to construct a series of airfields across northwestern Canada and the Alaskan Territory to shuttle American aircraft on Lend-Lease to the Soviets. Canadian planners located 12 airfield sites in their western provinces. The Americans were obliged to observe their declared neutrality prior to the Japanese attack on Pearl Harbor and Germany’s declaration of war in December 1941. The Pacific was the largest theater of military conflict in history stretching > 4500 miles (> 7200 km) between San Francisco and Yokohama. American military planners realized how vulnerable Alaska was to airborne attack and seaborne invasion. With America’s entry into the war against Japan and Germany in December 1941, 28 air bases were constructed during a 20-month period beginning in the spring of 1942, which connected Great Falls, Montana with Krasnoyarsk in Siberia, Russia. Known as the ASLIB (Alaska-Siberian Air Ferry Route), the Great Circle distance between Montana and central Siberia was 5145 miles (8285 km). The actual flight path was more than 6000 miles (9600 km), making it the longest air bridge of the Second World War. The Alcan Highway was the umbilical cord of Canadian and American presence, authority, and defense of the near-pristine frontier, which accommodated the transfer of ~ 8000 Lend-Lease combat aircraft, 56% of those that reached the Soviets during the war.

J. David Rogers
Prediction of Rework on a Construction Site Utilizing ANN Integrated into a BIM Environment

Rework is a prevailing problem in the construction industry that affects the project’s performance in a negative way whether in terms of time delay or cost overrun. Advances in Building Information Modelling (BIM) have helped in tackling coordination problems that are deemed to be one of the major contributors to the causes of rework. However, most of the research has been directed towards solving coordination problems during the design stage, while coordination problems resulting in rework during the construction stage are minimally addressed. This paper aims to present an interactive framework that predicts potential areas in the project that might experience rework during the construction along with the severity of rework in a BIM environment. In order to achieve the aim of this paper, a two-stage methodology has been adopted. First, extensive review of the literature has been conducted in the areas of rework, BIM, coordination problems and artificial neural networks (ANNs), followed by interviews and surveys to collect historical data for the past projects. Second, a model has been developed utilizing data collected in the first stage through the integration of BIM and ANN. The proposed model has been applied on a case study of an actual project to demonstrate the use of the developed model and test its efficiency. The output of the model application was a user form presenting the severity of rework in terms of probability of occurrence of 28.31%, project delay of 14.51% and expected cost overrun of 0.065%, in addition to a 3D-highlighted BIM model as per the contribution of each project element to rework. The framework proposed should aid decision-makers in taking the necessary actions in either mitigating or avoiding the possible rework and accordingly reducing possible delays and cost overruns.

Raghda Attia, Khaled Nassar, Elkhayam Dorra
Exploring the Essence of User Perspective in Studying Sustainability Aspects of Secondary Educational Buildings

Over the past few years, practitioners and researchers have worked together to establish frameworks that look into and evaluate the sustainability aspects of buildings using different measures and practices. Hence, this research paper introduces a three-tier framework for user perspective assessment in educational buildings. The first tier involves identification of the users’ perspective attributes that have a direct influence on the users’ perspective in existing buildings. These assessment attributes cover most of the users’ perspective areas in existing buildings. In addition, they are shown to be more comprehensive and to cover more areas compared against sustainability rating systems. The second tier is the weighting process of main factors stepping on the implementation of fuzzy analytical network process technique. The third tier is a fuzzy expert system that is to determine the overall user perspective index based on merging the weights of factors alongside their scores. The E.V. building in Concordia University was assessed to determine the impact of weighting and local context on the user perspective assessment.

Ghasan Alfalah, Abobakr Al-Sakkaf, Eslam Mohammed Abdelkader, Tarek Zayed Mohammed Abdelkader

Multi-objective optimization is getting more developed day by day to support the need of the construction industry, as it allows construction practitioners to have an inclusive solution that can take into consideration multi-aspects. Using genetic algorithms (GA) and goal programming (GP), this research is an attempt toward a more inclusive and wider multi-objective optimization model that can consider different aspects such as profit, time, resource usage, and quality, with different weights for each to aspect to reach a near-optimum solution according to the users’ priorities. The model was developed to work with three different construction methods for each activity. The developed model first optimizes each aspect independently, then provides a near-optimum solution considering all aspects together by maximizing profit and quality while minimizing the time and resource fluctuation with respect to the relative importance weights defined in the inputs. The model was applied to a case study where its data were inputted into the model. Several runs were performed first to find the optimum solution considering each aspect individually, then a final run to consider all aspects simultaneously. The results of the multi-optimization run were compared to the results of the individual runs, where variances were realized in the output of the multi-objective optimization from that of the optimum case of each individual aspect to achieve the optimum solutions that consider all of them simultaneously.

Mahmoud Amin, Athnasious Ghaly, Fredy Ayad, Ossama Hosny
Redefining Sustainability for Project Lifecycle Success

There are several barriers to the prioritization of designing infrastructure sustainably that have been observed in the infrastructure industry: ambiguity in what defines sustainability, perceived project costs project teams are reluctant to incur, and sustainable decisions that require innovative approaches in a traditional industry. By reframing rating systems to address these misunderstandings, project teams are encouraged to take an integrated approach to sustainability that develop higher quality and more economical project. Sustainability rating systems, such as the Envision Framework, have been developed to support project teams cut through the noise and successfully deliver sustainable projects.

Jill Roth
Watershed Analysis for Small Coastal Newfoundland Communities

Climate change is projected to increase frequency and magnitude of extreme precipitation events and increase temperatures that will impact infrastructure assets. As a result, Newfoundland’s many small, coastal and rural communities face increased risk from rising sea level, more intense precipitation and flooding, infrastructure failure and coastal and riverbank erosion. The response of a watershed to rainfall, and how development within a watershed will be impacted and, in turn, impact the hydrological response is vital to planning and design of infrastructure. The objective of this research is to look at land development and adaptation plans to minimize the climatic impacts on infrastructure and town assets. Two-dimensional (2D) watershed models (PC-SWMM) were developed for several small Newfoundland coastal communities. Scenarios representing multiple design storms for several return periods were run to assess vulnerability of storm-water infrastructure to potential land use and projected climate change. Model calibration was done using simulation metrics from the basin transfer method. The virtual watershed was designed to identify factors contributing to the high levels of vulnerability and risk and identify best adaptation and risk management strategies while considering uncertainties. Results highlighted vulnerable zones and some assets that require maintenance or require replacement to meet possible future flows. The most important highlight of the study was protecting natural infrastructure such as wetlands and greenspace to help reduce the pressure on the assets themselves. Future work should include better tracking of community assets and related information to help with assessment and planning and protect natural “green zones”. Using natural drainage helps keep infrastructure costs and helps reduce potential damage.

Kelly Miller, Nima Agh, Abena O. Amponsah, Joseph A. Daraio
David Thompson’s Surveying and Mapping of the Northwest of North America

The American Society of Civil Engineers and the Canadian Society for Civil Engineering have just jointly designated “David Thompson’s Surveying and Mapping of the Northwest of North America” as an International Historic Civil Engineering Landmark. David Thompson (1770–1857)—surveyor, map-maker, explorer, and fur trader for both the Hudson’s Bay and North West Companies—is considered “the greatest land geographer that the world has produced” (Tyrrell in David Thompson’s narrative of his explorations in Western America. The Champlain Society, Toronto, 1916, [13]), despite his serious visual impairment. Often accompanied by his Métis wife, Charlotte Small, he surveyed and mapped a vast region stretching from 45°N to 60°N latitude and from the western shores of Hudson Bay to the Pacific Ocean between 1790 and 1812. His 1814 Great Map, compiled from his surveys and those of Alexander Mackenzie, Simon Fraser, George Vancouver and his teacher Philip Turnor, laid the groundwork for development of the Northwest of North America. This paper briefly describes Thompson’s life and remarkable achievements.

David R. Gilbert, F. Michael Bartlett, Cole G. Bedford
A Brief History of the Kinsol Trestle

The Canadian Society for Civil Engineering will designate the Kinsol Trestle near Shawnigan Lake, BC, as a National Historic Civil Engineering Site in 2022. Canadian National Railways completed this massive structure, also known as the Koksilah River Trestle, in 1920. It is noteworthy for: (1) the scale and complexity of its original design and construction; (2) the operational and engineering challenges during its long railway service life; and, (3) the innovative rehabilitation design and construction to repurpose the trestle and extend its service and heritage value on the Cowichan Valley Trail which is part of the Trans Canada Trail. Built with a seven-degree curve, it is 44 m high, 187 m long and so remains today as one of the largest and highest wooden trestle bridges in Canada, representing an enormous feat of engineering and construction. It provided rail service and contributed to development of Vancouver Island for close to 60 years—the last train crossing was in June 1979. Rehabilitation of the trestle, completed in 2011, involved the replacement of 17 of the 46 bents using all-new wood and erecting under-slung custom-built steel trusses to “bridge” between the active bents. The remaining 29 original bents are simply left in place as inactive, non-load-bearing elements. This paper briefly describes the history of this remarkable structure.

Kevin Baskin, F. Michael Bartlett
Performance of VIP Insulated Building Envelope in Extreme Cold Climate

Energy use per person in Canada is among the highest in the world. Buildings consume about one-third of our total energy demand. This ratio is even higher in extremely cold climate regions. The most affordable and effective way to reduce energy consumption in buildings is to develop highly insulated building envelopes. There are several high-performance thermal insulations such as polymeric foam, aerogel, and vacuum insulation panel (VIP). Among these insulations, VIP offers at least five times the higher thermal insulating capacity than others. This unique characteristic of VIP makes it an ideal candidate for applications in the construction of new and retrofitted building envelopes. However, the uncertainty about the service life of VIPs in exterior building envelope applications is the issue yet to be addressed conclusively by the researchers and engineers. In recent years, researchers across the world have worked to address this issue, and several studies involving laboratory investigations and numerical modeling have been reported, but the lack of real-life field performance data is a significant impediment. This paper presents the critical analysis of the results from a field study conducted over 11+ years in Whitehorse, Yukon, Canada.

Phalguni Mukhopadhyaya, Vivian Chan, Doug MacLean, Juergen Korn
Performance Assessment of the Harmless Home

Construction is a significant contributor to environmental problems and climate change across various issues, such as resource consumption, energy demand, and waste generation. Research into sustainable building materials and their performance is required to minimize construction's environmental impact. The Harmless Home project aims to reduce this environmental harm through a holistic, sustainable approach with materials, water, electric, and septic systems, including solar panels to generate energy, water capture systems, and a new sustainable block material called Just BioFiber (JBF). This study analyzed subjective and objective measurements of four critical Key Performance Indicators: energy and emissions, water, indoor environmental quality, and cost. The project was evaluated using post-occupancy evaluation (POE) approaches. The International Initiative for a Sustainable Built Environment (iiSBE) Protocol was followed to investigate and analyze the results.

Rafael Wildson Costa Sousa, Thomas Froese
Energy Performance Evaluation and Building Energy Code Implementation of Multi-unit Residential Buildings: A Review

Rapid climate change is creating negative environmental and social impacts throughout the world. Greenhouse gas (GHG) emissions have been identified as the primary contributor to climate change. Excess energy consumption is the main reason for the increased atmospheric GHG level. Buildings are accountable for a major fraction of global energy use and GHG emissions. Therefore, building energy conservation initiatives and advanced building design concepts have attracted much attention to reduce energy consumption and associated emissions. Under the building sector, multi-unit residential building (MURB) energy demand is expected to increase by 179% by 2050 compared to the 2010 demand due to rapid population growth. Building energy codes and green building standards are available globally to improve the energy efficiency of MURBs. However, due to the complexity and the requirement of significant capital cost, the energy efficiency improvements of MURBs remain a challenge. This review aims to identify the existing building energy performance status of MURBs, currently available building energy codes and standards, key challenges and barriers that MURBs are facing while implementing energy efficiency standards. Moreover, the adaptation of lifecycle thinking to enhance the effectiveness of MURB energy efficiency was investigated from the lifecycle emissions and lifecycle cost perspectives. The findings of this study are aimed to assist the decision-making and mandate development process, building energy codes, and standards development. Moreover, it aims to open pathways to many future research directions of MURB energy performance evaluation by highlighting the necessity of research-based MURB performance evaluation techniques.

Ishanka Perera, Syed Asad Hussain, Rehan Sadiq, Kasun Hewage
Construction Lean Scoring and Benchmarking System

The construction industry is known to have several inadequacies leading to cost and schedule overruns. One of the popular methods that attempts to eliminate these inadequacies is lean construction, which is a set of principles and tools that aim to maximize value, eliminate waste and optimize efficiency. The success of lean construction depends on several factors. In other words, implementing lean construction tools does not guarantee reduction in cost and time overruns. There is a gap when it comes to identifying the factors that support the success/failure of implementing lean construction tools. In addition, the literature lacks a scoring system for measuring lean implementation. The goal of this research is to fill the abovementioned gap through developing and benchmarking a scoring system that utilizes lean principles to evaluate the “leanness” of construction projects. To this end, the authors: (1) identified the key factors that influence the leanness of construction projects; (2) determined the relative importance of the identified factors through an expert-based survey; (3) developed a scoring system called “the construction leanness score” for measuring lean implementation; and (4) benchmarked the leanness score representing the industry’s performance through collecting data from 30 construction projects. Results indicate that there are 27 key lean factors affecting the efficiency of lean implementation with the top two factors being early involvement of key stakeholders and trust between parties. The developed leanness score is considered the first of its kind to link leanness factors to project performance. Also, the developed benchmarking scale enables companies to compare their level of leanness to that of other companies in the industry. With this, companies are able to benchmark their performance, pinpoint the areas of weaknesses and take necessary actions to meet industry practices. Thus, improving the overall quality of construction projects, decreasing overruns.

Julia Said, Ibrahim Abotaleb, Islam El-adaway
Agent-Based Modeling for Delay Analysis Claims

Delays in a construction project have been a long-standing dilemma due to their inevitable nature. Consequently, time overrun in construction projects has been the main area of investigation by academic researchers and practitioners alike. When projects become more complex, the accuracy of quantifying delays can be an arduous process; without the proper quantification, this leaves contractors subject to the application of liquidated damages or losses. Various reasons for delays in the construction industry can lead to a ripple effect on certain path(s) of activities which cannot be easily traced throughout the lifetime of mega construction project with interdependent disciplines. The current methods within the delay analysis realm all involve a cumbersome process of data collection regarding the delaying events whether it would be utilized in a retroactive or prospective approach. Additionally, lack of proper documentation and records after the event has taken place will lead to an inaccurate delay analysis causing the upheaval of disputes between parties. Therefore, this paper allots for a real-time recording of delaying events through conducting delay analysis using agent-based modeling. This allows for the effect of delaying events to be instantaneously measured in terms of additional time suffered. Not only so, but agent-based modeling avoids the need for delay analysts to investigate the entirety of affected activities to link to the delaying event. A case study was then applied to a path of activities simulated using AnyLogic to validate the agent-based approach for delay analysis.

Julia Said, Mariam Elazhary, Yasmeen A. S. Essawy, Abdelhamid Abdullah, Khaled Nassar
Flow Field Around Wall Mounted Circular Cylinders with Strakes

Cylinders fitted with strakes have been studied as a method to suppress vortex shedding and mitigating vortex-induced vibrations. However, the effect strakes have on the horseshoe vortex (HSV) formed on the forebody-bed junction is not fully understood. In this work, a computational fluid dynamic (CFD) study is utilized to further investigate the flow characteristics. A Reynolds averaged Navier–Stokes (RANS) k-ω shear-stress transport (SST) turbulence model was utilized to carry out the numerical study. Simulations of the flow around the cylinder with diameter (D) of 40 mm were carried out. Three models were adopted: a cylinder with no strake and two straked cylinders with strake heights of 0.1D and 0.2D. The straked cylinders were situated such that at the base, the strakes were located at 60° to the approach flow. The cylinder Reynolds number was 28,000 based on the approach flow velocity. The drag coefficient of the no-strake cylinder case agrees well with published results. Wall shear contours along the bottom wall show a larger area of decreased wall shear stress both upstream and downstream of the straked cylinders compared to the bare cylinder. Vorticity contours and visualization of 3D fluid structures show that the HSV is formed further upstream from the pier face in the straked cases than the no-strake cylinder case. It was also observed that the HSV is extended further into the wake region for the straked cylinders. It was also found that the roll-up and subsequent development of the HSV is pushed farther from the base of the cylinder in the straked cases, with the distance increasing with strake height.

Mia Marrocco, Connor McGurn, Ram Balachandar
Framework for the Optimization of Flying Shuttering Bridges: A Hybrid Graph Theory and Simulation Approach

Bridge construction is considered as one of the major industries which reflect remarkable human evolution and creativity. Flying Shuttering is considered one of the robust techniques for a bridge’s deck construction because of its speedy construction feature. This paper presents a framework to help clients and consultants to make sound decisions regarding the selection of an optimized construction methodology in order to obtain better time and resource utilization. An intelligent framework with advanced computational tools and algorithms was designed to simulate and optimize bridge construction sequences for Flying Shuttering Construction Method, in order to obtain an optimized construction duration and resource utilization. It retrieves bridge elements geometric and topological information and maps them into the Bridge Elemental Graph Data Model (EGDM). By assigning the elemental construction method for each bridge element, the Bridge Elemental Construction Method Graph (ECMG) is formed. By searching the Bridge ECMG, possible Bridge construction sequences are retrieved, which are, then, simulated using a set of resource combinations in order to obtain the optimal Bridge Construction Sequence and, hence, recommend the Optimal Construction Method along with the Construction Schedule & Resources Utilization.

Yasmeen A. S. Essawy, Abdelhamid Abdullah, Khaled Nassar
Graph Representation for Emergency Egress Code Analysis

Code checking for emergency egress has been studied significantly which led to the continuous advancement and development of automatic code checkers. Yet, these checkers were only able to identify whether the building meets the code limitations or not and, in some cases, were able to take a step further and identify problem areas (if any). This paper presents a novel approach for code checking and analysis using graph theory. It maps floor plans into a simple directed acyclic Floor Plan Elemental Graph Data Model (EGDM). The Floor Plan EGDM, dual-graph representation, undergoes graph distance analyses in order to perform the first level of code checking, where egress paths are identified and examined against IBC emergency egress code limitations. The benefit of such a graph representation is not limited to performing traditional code checking, but further extends to include an innovative analysis of the floor plans to perform post-code checking. Post-code checking utilizes graph measures and search techniques on buildings that meet the code in order to identify areas for improvement and highlight critical areas where problems can happen. It is, also, performed on non-compliant buildings in order to highlight the problem areas and, hence, help the designer in solving these problems.

Yasmeen A. S. Essawy, Abdelhamid Abdullah, Khaled Nassar
Implementing Surrogate Modeling Techniques for Designing Optimal Building Envelops: A Case Study

Buildings are known to have significant environmental impacts. The life cycle approach for the measurement of CO2 emission and the life cycle costs of buildings are getting more important in the building design process. However, due to the complexity of the design process and the computational time of simulations and data processing, such methods are difficult to implement within optimization processes. This paper aims to apply surrogate modeling techniques as a solution to resolve the computational difficulties in the optimization process of building envelopes. The paper will describe the methods applied and will evaluate several aspects of the process, including the impact of the size of the training set on the prediction accuracy as well as the impact of different energy system efficiencies on the final optimum envelope design concerning seven objectives related to the economic and environmental performance of the building. The results showed that the size of the sampling test has a significant effect on the prediction accuracy; however, a balance between increasing the precision and computational time can be maintained by selecting an adequate number of samples. Moreover, it is found that to achieve the lowest total equivalent cost corresponding to the highest economic and environmental performance of the building, the minimum allowed window-to-wall ratio and the maximum permitted wall insulation thickness should be 0.15 and 0.02 m, respectively. The surrogate model was also shown to be efficiently capable of finding the optimum results according to the other objectives, including both economic and pure environmental aspects. Furthermore, the results provide some insights on how the variation of energy systems’ efficiency might affect the optimum solutions in the optimization process.

Shahrzad Monshet, Thomas M. Froese, Ralph Evins
Methodological Analysis of KPIs to Evaluate Contractor Performance of the Construction Project

Measuring construction performance is one of many important tasks in completing a construction project. For the contractor, it allows visibility of high-performing areas or low-performing areas that need to be addressed. It is essential for proper forecasting to ensure budgets are accurate and for accurate scheduling, to ensure there is adequate time and the proper number of workers to complete the project. When measured over multiple projects, it can also serve as a mechanism to evaluate contractors for future projects by assessing past performance. One such method of measuring performance is utilizing key performance indicators (KPIs) which are not only used in the construction industry but in all other areas of business. There are many KPIs that can be utilized in measuring construction performance including specific ones relating to productivity, safety, and quality. This paper introduces the method of identifying the most significant KPIs which will objectively help owners evaluate contractor performance. The study explores the many different types of KPIs that owners currently use to evaluate contractors’ performance. Projects for an owner can vary in scope and complexity significantly from one to the next and can be located in many different geographical locations. All these factors change how difficult it is to construct a project effectively and affect the cost of the project in many ways. The methodology developed here in this paper identifies the normalization of the factors in order to establish a performance measurement that can allow projects to be accurately compared against one another for performance assessment. The major focus of this study is to develop a framework using key performance indicators that can be used by owners in measuring the ability and efficiency of their teams and contractors to execute projects.

Ayesha Siddika, Mohammad Masfiqul Alam Bhuiyan
Achieving a 100-Year Design Service Life on Wastewater Projects

The primary cause of premature deterioration on wastewater infrastructure is due to the lack of or improperly installed protective measures, not the structures themselves. Using newly developed design, manufacturing and installation protocols, Engineered Containment has pioneered a 100-year design service life guarantee. The concrete protective lining protocol eliminates the failure modes of traditional lining systems (both epoxy and embedment liner) while reducing costs at the front end and through the lifecycle of the structure(s). This cradle-to-grave approach, which is currently being implemented on strategic projects across Canada, provides owners and stakeholders tangible assurances regarding service life and warranty. Innovations are based upon the results of an in-depth review of current industry modalities and a mechanical and chemical review of various products utilized for concrete protection.

James P. Eng. Teppan


Water Model Development for Freeze-Protected Water System in Iqaluit, Nunavut

Water for the City of Iqaluit, the capital city of the Canadian territory of Nunavut, is supplied from a nearby lake which feeds by gravity to a water treatment plant. Treated water is stored in a two-cell reservoir prior to distribution into seven independent water districts through an insulated and buried piping network. The water districts are unique because, in addition to insulated piping, each district has an independent recirculating water supply and water reheat system to provide freeze protection. This makes the hydraulic configurations of each district more complicated than a water system in warmer climates. Two of the districts are pressurized with independent booster pumphouses, and the remaining five districts are supplied by gravity from the reservoir. The City is advancing a project to develop a water model of its water distribution network which will provide a detailed understanding of the current system operations and provide a tool for system troubleshooting as well as planning for system upgrades and expansions. Model results will also be utilized for thermal analysis of the water districts. This will provide opportunities for optimization of the heat addition to the water supply to be explored which may provide some significant cost savings on the energy used to reheat the recirculating water. The first phase of the project has been completed with the objective of developing a working water model using all the system data based upon records of construction and operational data available for each of the seven water districts. This stage of the work has identified system deficiencies for maintenance and repairs. Phase 2 of the project will complete hydrant flow tests throughout the distribution system required to calibrate the water model.

Marilyn Fanjoy, Ken Johnson, Marc Lafleur, Eric Bell, Simon Doiron
Hydrology and Water Balance Study for the Canadian High Arctic Community of Grise Fiord

In the Canadian Arctic, drinking water availability is scarce and vulnerable to changes such as climate change impacts and increasing community development. A hydrological and water balance study was completed to determine if various surface water sources that rely on snowfall and snowmelt-generated runoff could meet current and future 20-year water supply needs for the High Arctic Nunavut community of Grise Fiord, the most northerly community in Canada. The study is focused on a coarse-resolution analysis to characterize annual watershed yield versus expected water use of the community and accounts for annual municipal water supply usage, population growth, and potential impacts of climate change. High-Resolution Digital Elevation Models were used to delineate potential watersheds using ArcGIS. A water balance model was used to predict the annual water yield from each potential watershed using historical and projected future climate data. Climate scenarios were analyzed using below-average values for precipitation rates and above-average values for evapotranspiration rates to account for worst-case scenarios. The watersheds represent nival regimes which are characterized by negligible winter flows (typically between October and early May), followed by significant flows in the summer from ice melt and thawing snowpack. From the analysis, the existing runoff source at Grise Fiord is not reliable or sufficient to meet the future water supply needs of the community. It was recommended that the community uses the alternative primary water source identified in the study (Airport River) as this source can meet the community’s future needs. The alternative water source will require constructing a new water intake and raw water storage infrastructure (storage tanks) in addition to the new water treatment facility.

Chris Keung, Ken Johnson, Joel Gretton, Aurangzeb Alamgir


Assessment of Key Imperatives for Enhancing Precast Adoptability in Developing Countries

Precast concrete’s modular application has proved prevalent within the construction industry over the past decades. The road has been paved for wider use of modern precast concrete in the construction industry. Unfortunately, use has been limited in emerging nations despite the booming and ever-growing construction industry. The main objective of this study is to assess the status of precast concrete in emerging regions attempting to pinpoint both the advances and barriers associated with its use. The Egyptian market is an example of an emerging market where a full set of material products is considered. Data analysis including surveys from site visit interviews is used to incorporate actual market conditions and consideration into the findings of this work. Summarized trends of the Egyptian precast concrete industry with analysis of their impact on market strength and value-added were observed. Recommendations are provided for concrete societies and the construction industry by in large toward better utilization of precast concrete within an emerging region like Egypt. From the surveys and data collected evidently Egypt as a developing nation showed precast construction possesses roughly 5% of the load bearing construction market giving it room to penetrate and possess more market share. Modular units are the major application of precast concrete technologies considering surveys and feedback forms within this thesis. A significant number of apple-to-apple cost comparisons were made showing the capability of precast methods of being a cost saving measure reaching saving of up to 35% in comparison with traditional construction works, enhancing the understanding of a typical user in a developing region the power points of using precast construction in comparison with traditional. The reader will be able to signify the perceptions taken by professionals in the market aiming to utilize precast to pursue more modern and efficient approaches to modular building.

Mostafa Abdelatty
Alkali-Activated Concrete Workability and Effect of Various Admixtures: A Review

Alkali-activated concrete (AAC) is getting popular as a sustainable alternative for ordinary Portland cement concrete. Hence, questions regarding potential adaptation for existing concrete technologies to deal with performance issues of the new concrete type were raised. On top of these technologies, the efficiency of various admixtures and their interactions with the AAC's ingredients, hydration products, and microstructure development represents a knowledge gap. This paper reviews the workability requirements for AAC and the efficiency of various admixtures to achieve the targeted performance. The stability of admixtures in the alkaline medium, optimum dosages, and interaction with the activation process were highlighted. The reported data are anticipated to guide engineers in selecting suitable admixtures to achieve the desired workability while maintaining adequate performance.

Nourhan ELsayed, Ahmed Soliman
Inconsistencies and False Assumptions Related to the Determination of Design Values for FRP Systems

Fiber reinforced polymer (FRP) materials have been used for over half a century in the aerospace, marine and automotive industries. During the last few decades, civil and structural engineers have begun to see the advantage of these materials as a means to retrofit and rehabilitate existing structural members in buildings, bridges and other civil infrastructures. There are many guidelines and some codes that help engineers to design these systems for various structural applications. Despite the increase in acceptance of these systems there remains some major confusion related to the most fundamental part of the design process… How do you determine the characteristic values/design properties of the material? Some of the confusion stems from the assumption that all fiber reinforced polymers (FRPs) use the same method to report their design values… they do not. Or that the ASTM standards being used by the industry provide consistent design properties… they do not. Some engineers assume that following CSA S806, CSA S6-06 or ACI 440.2R-17 will get them consistent design properties… it will not. These issues have created confusion, and they have not been appropriately addressed. This paper will point out the various inconsistencies and false assumptions in more detail while presenting a suggested solution that has been in practice in other industries using FRP materials.

Scott F. Arnold, Reymundo Ortiz
Design and Experimentation of Pollution Absorbing Blocks (PABs)

Due to the worldwide increase in air pollution which is responsible for a good percentage of diseases, indoor air quality is now a major concern to people since there is a much higher capacity to control indoor air pollution than outdoor. Therefore, this study aims to develop a block that can filter the air from suspended particulate matter ranging from 2.5 to 10 µm while acting as a passive filtration system installed as the exterior wall of the building. This block can be efficient in any type of building. Moreover, this will enable air to enter the building through an inlet in the block facing the outside of the building and exit the block through an outlet located inside the building. Between the inlet and the outlet of the block, air circulates in a cyclone movement due to the inner design of the block. The developed blocks potentially resulted in an internal centrifugal force for the air passing through that can separate the particulate matter and contribute to more pure air. In that sense, the overall aim of this work is to evaluate a simplified and effective walling system incorporating pollution absorbing blocks (PAB) and contribute significantly to better air quality. In order to meet this aim, a block was specifically designed. Air quality test was performed in order to assess the effectiveness of the cyclone movement filtering process and ensure its efficiency. This is conducted in parallel with conventional compressive strength tests as well as absorption tests as two of the key tests contributing to the integrity and performance of the wall system. This work did undergo different cycles of enhancements to produce a more environmentally friendly wall system and to minimize the drawbacks of non-purified air within the interior of buildings. The main aim of this research is to develop a structurally functional block, which is able to filter the air from a specific range of particulate matter, consequently, contributing to enhancing indoor air quality.

Abdelrahman ElDokhmasey, Loay Hassan, Mira Nessim, Omar Rabie, Mostafa Abdel Aziz, Salah El Gamal, Farida Said, Mohamed AbouZeid
Piezo Monitoring of Concrete—A Review Paper

Monitoring of reinforced concrete (RC) structures at various stages of their life cycle remains a key to the overall maintenance strategy. Despite being the most popular construction material, RC remains vulnerable to shrinkage cracks, reinforcement corrosion, freeze–thaw, sulfate attack, etc. This adversely affects the performance of the infrastructure and in extreme cases results in the overall failure of the structure. In order to check the augmenting repair and maintenance costs, the use of non-destructive testing has gained immense popularity in the last decade. Several techniques such as fiber optics, wave propagation techniques, and vibration monitoring techniques have been proposed to detect any progressive damage taking place within concrete at different stages. Recently, the use of lead zirconate titanate (PZT) piezo patches has been used for structural health monitoring (SHM) of RC structures. This paper sheds light on the development of the piezo monitoring technique using PZT patches as a potential NDT. A detailed analysis of the electrical impedance (EI) method and wave propagation (WP) methods reported for the condition assessment using PZT patches has been described. The practical challenges associated with the use of PZT piezo patches for NDT in both EI and WP methods are addressed. Finally, the paper discusses the required areas of PZT research investigation to make it a viable NDT for RC structure.

Manisha Madipalli, Sakshi Aneja, Ashutosh Sharma, Rishi Gupta, Caterina Valeo
Evaluating the Performance of Alkali-Activated Materials Containing Phase Change Materials: A Review

Nowadays, many researchers are investigating the behavior of phase change materials (PCMs) in construction materials. They are trying to utilize their ability of heat storage to reduce the energy usage for maintaining comfort conditions in buildings. Although there has been extensive research during the past decades on PCMs’ application in ordinary Portland cement (OPC) concrete, limited studies were done on alkali-activated materials (AAMs). This paper reviewed and identified the effects of PCMs addition to AAMs. Moreover, a comparison between the effect of PCMs in OPC and AAMs has been done. Results showed similarity for the effect of PCMs on OPC and AAMs including lowering the mechanical strength while increasing the thermal capacity. The heat storage of the PCMs inside the AAMs sample can also help the curing process. This paper can help the in-situ engineers which have a better perspective for selecting the proper mix design when using these materials.

Amirhossein Golizadeh, Farshad Meftahi, Ahmed Soliman
Experimental Investigation on Compressive, Tensile, and Flexural Strengths of Concrete with High Volume of GGBS, Fly Ash, and Silica Fume

An experimental investigation was carried out to study the performance of high-strength concrete with a high volume of mineral admixtures. Two concrete mixes were prepared, an ordinary concrete and high-strength concrete with target compressive strengths of 35 and 90 MPa, respectively. The ordinary concrete was produced without mineral admixtures while the high-strength concrete was produced using ground granulated blast-furnace slag (GGBS), fly ash, and silica fume in a weight ratio of 30%, 20%, and 10%, respectively. For each concrete mix, twelve cubes, six rectangular prisms, and twelve cylinders were prepared simultaneously. The experimental program consisted of destructive tests including compressive, tensile, and flexural strength tests as well as non-destructive tests including Schmidt hammer and ultrasonic tests. In the destructive testing part of this study, the cubes were tested in compression, the prisms were tested in flexure, and the cylinders were subjected to splitting tensile load. The compressive strength at 28 days was 41.72 MPa for ordinary concrete and 96.53 MPa for high-strength concrete which is 19.2% and 7.26% higher than the target strengths of the two mixes, respectively. The experimental flexural strength of the high-strength prisms was 6.17 MPa which is 8.45% higher than the target value. The splitting tensile strength of high-strength concrete was 1.59 times that of ordinary concrete. Concrete made by a high volume of GGBS, fly ash, and silica fume ratios demonstrated superior mechanical properties which exceeded the target design strengths.

Alaa Al Hawarneh, Saif Aldabagh, M. Shahria Alam
Nano-Modified Concrete Incorporating Phase Change Material Under Cold Temperature

Stringent requirements (enclosures, temperature thresholds, etc.) are typically prescribed in codes for cold weather concreting, which entail substantial costs. Nano-silica has the capability of improving the hydration process and concrete performance due to its high surface area and vigorous reactivity, which may be utilized to counteract cold temperatures. In this study, five concrete mixtures were prepared to investigate the effect of a freezing temperature (-15 ℃) on their mechanical and physical properties. Combinations of ordinary cement and nano-silica sol were incorporated in concrete as the main binder components. All mixtures comprised calcium nitrate-nitrite as cold weather admixture systems (CWAS) to depress the freezing point of mixing water. In addition, nano-silica or nano-clay powders saturated with phase change material (PCM) were added to the mixtures as an internal curing aid. All mixtures were cured at -15ºC to simulate actual field conditions. The mixtures’ performance was assessed based on setting times, early- and late-age compressive strengths, fluid absorption, and hydration development. The coexistence of nano-silica and CWAS, with the addition of PCMs, especially in the case of nano-silica powder as a host, markedly improved the overall performance of concrete. This indicates the promising use of nano-modified concrete cured internally with PCMs for cold weather applications, without the need for heating practices.

A. M. Yasien, M. T. Bassuoni, A. Ghazy
Challenges for the Development of Artificial Intelligence Models to Predict the Compressive Strength of Concrete Using Non-destructive Tests: A Review

Artificial intelligence (AI) can be used to solve complex problems in a short amount of time or give machines the ability to make decisions based on previous data. In recent years, AI has been used in many fields such as medicine, robotics, and aerospace. However, in many fields of the construction industry, such as structural engineering, AI has not been widely used in practice. One potential application of AI that has been the focus of several research efforts over the years is to predict the compressive strength of concrete in existing reinforced concrete (RC) structures. Accurate estimation of concrete strength of existing RC structures is an important challenge for engineers. The most reliable method to obtain the compressive strength of concrete is to perform the core test (destructive test) which causes damage to the structure and is very costly and time-consuming. Moreover, due to safety or project conditions, it is not always possible to extract cores. Two common non-destructive methods that correlate with the compressive strength of concrete are the ultrasonic pulse velocity (UPV) and the rebound hammer test. Several equations and regression models have been proposed to estimate the strength of concrete based on these two non-destructive tests. Each of these models is limited by specific boundary conditions, and the equations are not universally accurate or reliable. In recent years, studies have been conducted to develop AI models based on non-destructive testing of concrete. This paper first reviews the studies conducted in this field and then discusses the remaining challenges and explains why; despite several years of studies around the world, there is still no accurate and usable model for the industry. Finally, advantages for future AI models are described.

Seyed Alireza Alavi, Martin Noël
Partial Cement Replacement in Concrete with Gypsum Powder Recycled from Waste Drywalls

Construction industry is one of the most significant contributors to environmental issues in today’s world. For this reason, sustainable approaches in building industry have always been sought by researchers in this domain. Cement manufacturing process, for example, emits considerable amounts of greenhouse gases contributing to global warming. Replacing cement with other materials which have less environmental footprints has been considered a solution. Construction and demolition waste disposal, also, could cause environmental issues in landfills. Gypsum drywalls account for a considerable amount of construction waste which contains a noticeable amount of gypsum. Utilizing recycled gypsum from waste drywalls as a partial replacement for cement in concrete could address both problems regarding the impact of construction on the environment. In this study, recycled gypsum powder from waste drywall will be used as a partial replacement for cement in concrete. Five concrete mix designs which include 0, 10, and 20% of recycled fine gypsum powder and whole gypsum are considered for this study. Since it has been proven that gypsum does not function well as the only partial replacement of cement, 50% of each mix design is dedicated to fly ash. Three cylindrical (100 mm x 200 mm) specimens of each mix design are planned to be tested at 7, 28, and 90 days. This paper will introduce the combination of fly ash and recycled gypsum as a sustainable replacement for cement in concrete and suggest more environmentally friendly concrete for our infrastructure.

Kasra Takbiri, Pedram Sadeghian
Nano-modified Slag-based Cementitious Composites Reinforced with Multi-scale Fiber Systems

This study responds to the need for improving the overall performance of concrete infrastructure to achieve longer service life, fewer cycles of repair, and reduced life-cycle costs. Hence, novel high-performance fiber-reinforced cementitious composites were developed using various types of nano-materials and fibers. The composites developed in this study comprised high content (50%) slag by mass of the base binder (700 kg/m3) as well as nano-silica or nano-crystalline cellulose (produced in Canada). In addition, nano-fibrillated cellulose (NFC), produced in Canada, and a novel form of basalt fiber strands enclosed by polymeric resins called basalt fiber pellets (BFP), representing nano-/micro- and macro-fibers, respectively, were incorporated in the composites. The composites were assessed in terms of early- and late-age compressive strength, flexural performance, and resistance to freezing and thawing cycles. Generally, the BFP reduced the compressive strength of the composites, but the co-existence of nano-materials and NFC alleviated this trend. Furthermore, all nano-modified composites with multi-scale fibers showed notable improvement in terms of flexural performance (post-cracking behavior, residual strength, and toughness) and resistance to frost action. Thus, they can be used in a suite of infrastructural applications requiring high ductility in cold regions.

O. M. Hosny, A. M. Yasien, M. T. Bassuoni, K. Gourlay, A. Ghazy
Applications of Agro-waste in the Construction Industry: A Review

Agriculture waste is considered as one of the most crucial concerns which negatively affect the environment. Hence, the trend of using agro-waste in the construction industrial has become the focus of recent research studies. Implementation of agro-waste in concrete mixtures as a replacement material for various ingredients had several effects on mechanical properties, structural behaviour, durability, and sustainability. Agro-waste can replace fine and coarse aggregates and act as a filler and/or reinforcing material based on its characteristics. This paper reviewed the use of agro-wastes in different construction applications and their effects on various properties, including mechanical, acoustics, and thermal. In addition, the paper will highlight the ecological and environmental impact of the use of such agro-wastes.

Arman Hatami Shirkouh, Ahmed Soliman, Joahnn Palacios, Stéphane Godbout
The Compressive Strength of Ultra-high Performance Concrete at Elevated Temperatures

Ultra-high performance concrete (UHPC) has significant strength and performance advantages for structural applications that can lead to thinner and lighter structures, but one drawback is that UHPC can be affected by explosive spalling at elevated temperatures. Synthetic fibres (e.g. polyvinyl alcohol (PVA) and polypropylene (PP)) are commonly added to help mitigate explosive spalling. Although this practice is common, most of the previous research efforts focused on the residual strength of UHPC after exposure to elevated temperatures. Research is lacking in the performance of UHPC under simultaneous load and heat effects. This paper presents compressive strength test results at steady-state temperatures (25, 300, 400, and 500 °C), along with residual compressive strength tests after exposure to 500 °C. The results showed the UHPC reinforced with 2% by volume of PVA fibres withstood exposure to elevated temperature without explosive spalling. The compressive strength gradually reduced with the increase of the elevated temperatures. At 25, 300, 400, and 500 °C, the average compressive strength was found to be 156, 124, 118, and 83 MPa, respectively. The retained strength ratio at 300, 400, and 500 °C was found to be 0.7930, 0.7544, and 0.5315. The residual compressive strength after exposure to 500 °C was 95 MPa which is slightly higher than the steady-state compressive strength.

Branna MacDougall, Hamzeh Hajiloo, Salah Sarhat, John Kabanda, Mark Green
Development of Self-Energy Storing Engineered Cementitious Composites

In this study, microencapsulated phase change materials (MPCMs) were incorporated within engineered cementitious composites (ECCs) in attempt to develop a new cementitious material capable to self-store the thermal energy while presenting optimized ductility performances. For this purpose, MPCMs with a phase transition temperature of 18 °C and 6 °C were added to ECC mixtures at 10, 20, and 30% by silica sand replacements. The self-heat storage capacity was tested by assessing the inner temperature change of ECC system placed in an environmental chamber regulated at fluctuated temperatures varying from −10 °C to 32 °C with constant relative humidity. The effect of MPCMs on the fresh and mechanical properties of ECCs was investigated by measuring the flow diameter, compressive and flexural strengths, and deflection and cracking performance of different MPCM-based ECCs. In addition, SEM/EDS analysis was performed on core samples of various ECC mixtures to characterize the effect of MPCM on the microstructure of ECC. The results revealed that the heating/cooling behavior of ECCs highly improved with increased MPCMs contents. Mechanical strengths were not highly influenced by the use of MPCMs, especially at 10% and 20%, thus allowing the development of high ductility ECC mixes with thermal-energy storage ability under high and low temperatures.

Richard Malantic, Hocine Siad, Mohamed Lachemi, Mustafa Sahmaran


Estimating Lake Evaporation for the South Saskatchewan River Basin of Alberta

Evaporation from a reservoir’s surface is an important component of water balance calculations. Using long-term (1955–2020) climate data from Alberta Climate Information Service, we estimated gross and net lake evaporation from fifteen reservoirs in the South Saskatchewan River Basin of Alberta based on Morton’s complementary relationship-based model. We ranked the reservoirs based on various criteria to identify the reservoirs with significant evaporative losses. The net maximum annual evaporative loss from fifteen reservoirs ranges from 659 cubic decameters (dam3) to 21,251 dam3. Our analysis reveals that there are six reservoirs with significant net evaporative losses (e.g., > 70% of total annual maximum net loss). We also performed additional evaporative loss calculations on these six reservoirs using the Prairie Farm Rehabilitation Agency (PFRA)-modified Meyer’s method. We compared the differences between the two evaporation models. Our results show that Morton’s model shows better consistency than PFRA-Meyer’s model considering data availability and the sensitivity of evaporation estimates. We also applied Morton’s shallow lake and deep lake models for those six reservoirs to analyze the seasonal variabilities in evaporative losses. Although on an annual scale, both models provide similar results, we demonstrated that the deep lake model is able to capture monthly variabilities better than the shallow lake model.

Zahidul Islam, Shoma Tanzeeba, Carmen de la Chevrotière, Prabin Rokaya
Unbox Your Ideas—the Benefits of Integrated Design

Traditional project delivery in North America is often fraught with design changes, budget and schedule overages, and adversarial relationships between the design and construction teams. Rather than the traditional approach of distinct planning, design, and construction teams, each of whom operate in a “black box” passing a project along from phase to phase, the concept of an Integrated Design Process (IDP) is to have one integrated team work together to consider risks and opportunities across project phases.

Quin MacKenzie
Evaluation of Process-Based Ensemble Models for Forecasting Point-of-Consumption Free Residual Chlorine in Refugee Settlements

Waterborne illnesses are a leading public health concern in refugee and internally displaced person (IDP) settlements. Controlling the spread of these illnesses can be particularly challenging as pathogens can be introduced into previously-safe drinking water during the post-distribution period of collection, transport, and household storage. Free residual chlorine (FRC) is often used in these settlements to prevent recontamination of drinking water, and thus, it is critical that at least 0.2 mg/L of FRC is available up to the point-of-consumption. Chlorine decay models can be used to determine the chlorine dose required to maintain this residual; however, post-distribution FRC decay is highly uncertain due to many immeasurable factors that vary substantially from user to user within a site. Traditional deterministic FRC decay models are unable to quantify this uncertainty. Therefore, there is a need for improved modelling that quantifies uncertainty in FRC decay. Ensemble forecasting systems, which consist of collections of models as opposed to a single standalone model, can quantify this uncertainty by generating probabilistic forecasts of FRC. This study presents a novel use of ensemble techniques to generate probabilistic forecasts of FRC decay for the post-distribution period in refugee and IDP settlements. The two alternatives considered for determining the decay parameters for the ensembles were a resampling approach with least-squares regression and a quantile regression-based approach, both using six different FRC decay equations. These approaches were tested using a six-month operational water quality dataset collected from a refugee settlement in Bangladesh in 2019. The quantile regression-based ensembles produced more reliable forecasts, and better capture of observed values, as compared to resampling with least-squares. Of the FRC decay equations considered, the parallel first-order decay equation produced the least quantile error when compared to the other decay equations considered. This demonstrates that ensemble forecasting systems effectively quantify uncertainty when modelling post-distribution FRC decay. These findings can be used to develop improved FRC guidance for humanitarian responders working in refugee and IDP settlements.

Michael De Santi, Everett Snieder, Syed Imran Ali, Usman T. Khan, Jean-François Fesselet, James Orbinski
Sustainable Management of CO2 Generated by a Wastewater Treatment Plant

A substantial CO2 emission has been generated by wastewater treatment plants (WWTPs) due to various biological processes. Since the most important consequences of increasing CO2 in the atmosphere are global warming and climate change, there is a necessity to mitigate CO2 emissions in a sustainable way, particularly, when inorganic carbon can be converted to a valuable product. This paper proposes a novel management of CO2 generated by WWTP through its capturing and converting into a fuel, which can be used in-situ. A newly developed electrochemical device, under a constant direct current (DC), was able to convert carbon dioxide to fuel at ambient conditions without additives. These conditions (temperature and pressure) seemed to be satisfied parameters to achieve the sustainable electrochemical transformation of CO2 into a green fuel (methanol). The study permitted to optimize technological parameters, such as voltage gradient, gas flowrate, input gas period, and temperature, in order to generate the best conversion of CO2 to methanol. The continuous flow device was set for final conditions resulting in the predominant methanol generation. Under room temperature, at a voltage gradient of 8 DCV/cm, 60% of CO2 found to be converted to methanol after only 20 min of influx time. Therefore, the developed electrochemical device can convert CO2 produced at WWTP into methanol, which may be used as a fuel or in denitrification facilities at the same WWTP. The proposed device is one of the useful approaches to a sustainable GHG management at WWTP, permitting to store energy and contribute to solving the global warming and climate change problems.

Soodeh Abedini, Maria Elektorowicz, Sasan Fazeli
Residual Methane Generation Capacity of Waste Residue in a Landfill Bioreactor: Case Study of Calgary Biocell

With the aim of evaluating the environmental economic value of Biocell technology, in this paper, excavated waste residue (EWR) from the Calgary Biocell was characterized for the first time. The objective was to find the carbon offset of the Calgary Biocell project through biochemical methane potential (BMP) assay. The EWR samples were collected from different locations within the Calgary Biocell, and the physical and chemical characteristics of the individual EWR samples were evaluated following the standard methods. The BMP assays were conducted using the modified solid-phase method that represent condition of landfills more accurately. A composite sample which was a mixture of all EWR samples was prepared to represent the entire Biocell condition. Laboratory batch experiments were conducted using the biodegradable fraction of EWR to evaluate the methane (CH4) generation potential (Lo) and the first-order rate coefficient (k) values of Calgary Biocell. Based on the BMP assays, it was shown that the excavated waste from the Calgary Biocell has gone through more degradation (i.e., with a production of 16.81 ± 2.9 mL CH4/g TS) compared with the other studies on excavated waste, emphasizing effectiveness of Biocell technology in terms of waste degradation.

T. Abedi, J. P. Hettiaratchi, D. Pokhrel
Decarbonized Natural Gas Supply Chain with Low-Carbon Gaseous Fuels: A Life Cycle Environmental and Economic Assessment

Continuous growth in the economy has caused an increasing demand for energy resulting in numerous environmental concerns. Despite the popularity gained by renewable energy, certain economic activities still require fossil fuels. Among existing fossil fuels, natural gas (NG) plays a critical role in ensuring Canada’s energy security. However, the Canadian oil and gas sector is a major contributor to national greenhouse gas emissions. Therefore, rigorous actions are required within the NG industry to ensure sustainability in its operations. Hydrogen and renewable natural gas (RNG) are identified as low-carbon gaseous fuels capable of decarbonizing the NG supply chain. RNG has already been used in the market, whereas hydrogen is gaining increased attention from utilities due to its ability to produce in higher capacities than RNG. Moreover, hydrogen blending into NG systems is piloted worldwide as an effort to reduce emissions from building heating and other carbon-intensive applications in the energy sector. However, the feasibility of different NG supply chain configurations coupled with low-carbon gaseous fuels is still under question due to multiple economic and environmental factors. Therefore, this study attempts to conduct a cradle-to-grave life cycle environmental and economic assessment of different NG supply chain configurations coupled with hydrogen and RNG. A life cycle thinking-based methodological framework is proposed to evaluate and compare the different supply chain configurations. The framework is presented with a case study for BC’s natural gas sector with six supply chain configurations for the Canadian NG industry. The life cycle environmental and economic performance of the six configurations were evaluated using life cycle assessment and life cycle costing. The performance was integrated using the eco-efficiency analysis tool. According to the study results, replacing RNG with NG is shown to be the most desirable option. However, hydrogen blending with natural gas is still of high cost. Furthermore, the costs and environmental impacts of hydrogen production vary with its production method. Hydrogen production with electrolysis has lower impacts compared to hydrogen production with steam methane reforming (SMR). The findings from this study are geared toward enabling decision-makers and investors to gain a more holistic view of investment decisions related to green energy initiatives in the NG sector.

Ravihari Kotagodahett, Kasun Hewage, Rehan Sadiq
An Optimization Model for Selecting Combinations of Crops that Maximize the Return Inside Self-sustainable Greenhouses

The main purpose of this research is to outline the development of an optimization model for selecting a combination of crops that have the maximum equivalent annual cash flow (EACF) inside a self-sustainable greenhouse. A self-sustainable greenhouse will require to provide the total energy required for irrigation (pumping energy) for the combination of crops that will be selected. Photovoltaic (PV) energy is chosen as the source of renewable and sustainable source of energy. The research was conducted by establishing the required database, generating different scenarios, assessing the economic performance along the project life, forming the optimization model using genetic algorithm (GA), and systemizing the model using Microsoft-Excel. The database includes two main parts: data on the crops’ requirements and data on the PV pumping system. Typically, irrigation experts provide the required pumping energy, and then, the designer sizes the PV system based on the given value by the available solar energy/m2. This leads to over design of the system which leads to higher cost. In this research, the impact factors, i.e., location, soil type, water source, crop types and their planting season, and PV water pumping (PVWP) system characteristics, were considered for developing the optimized model. As PVWP system depends on available solar energy which fluctuates overtime, the output (water) also fluctuates. Therefore, optimizing the relation between the output (pumping energy required) and input (solar energy available) will lead to meet the requirements for irrigation in the best manner possible. This study has led to the development of a general model for optimal sizing for a ground mounted PV systems that meets the required energy needs for irrigation for a combination of crops that maximize the return.

El Nahas Eman, Hosny Ossama, Serag-Eldin Amr
Sustainability Assessment of Applying Circular Economy to Urban Water Systems

Humanity has been overexploiting essential resources such as water, energy, and nutrients. Hence, the recovery of the said resources in Urban Water Systems (UWSs) has become not only advisable but a necessity. In this context, the circular economy is an approach that focuses on regenerating natural capital, closing resource loops, and decreasing the amount of waste discharged into the environment. While some works are available accounting for wastewater reclamation, few papers also evaluate the recovery of biosolids and energy. This research aims to analyze the environmental and economic sustainability of UWS, considering circular economy strategies through resource recovery. Also, this study aims to identify the main processes impacting the life cycle of UWS and whether sustainability is enhanced in the resource recovery alternatives. The Life Cycle Assessment (LCA) and the Life Cycle Costing (LCC) methods were applied to five alternatives of UWS considering a conventional scenario, as well water, energy, and biosolids recovery alternatives. In the end, a water–energy– nutrients nexus scenario is analyzed. The study uses four LCA methodologies: (1) IPCC 2013 for the Global Warming Potential (GWP) category, (2) Cumulative Energy Demand (CED) for the energy input evaluation, (3) ReCiPe Endpoint (H/H) V1.13/ World, and (4) aware, to estimate water footprint. Results show that the environmental impacts estimated by the IPCC, AWARE, and CED are similar to the considered alternatives. Furthermore, the LCC was conducted using the net present value method. The results highlight that the energy recovery scenario shows the best environmental performance, while the water–energy– nutrient nexus UWS has the best economic performance. In the final aggregation, the biosolids recovery had a better sustainability performance. It is important to highlight, however, that the best sustainable option will vary depending on the location and system type.

Thais Ayres Rebello, Gyan Chhipi-Shrestha, Kasun Hewage, Rehan Sadiq
The Influence of Nanoparticle–Cell Ratios on the Disinfection of Escherichia Coli by Silver and Zinc Oxide in Low Concentrations

Silver nanoparticles (AgNPs) embedded within ceramic water filters have gained popularity as a methodology for improved disinfection over filtration alone, though concerns exist regarding their cost, health, and ecological impacts. Research into the replacement and/or supplementation of AgNPs with less expensive NP alternatives is therefore of interest. The influence of NP and microbial contaminant concentrations on disinfection performance, however, require further exploration and elucidation. This research thus investigates the potential synergistic disinfection of AgNP and zinc oxide (ZnO) at various co-application concentrations when challenged by three levels of Escherichia Coli contamination. In this study, 1 L of water with dissolved organics, micronutrients, and E. Coli in concentrations of 102, 103, or 105 CFU/mL was treated with AgNPs and/or ZnO. AgNPs concentrations ranged from 0.5 to 20 ppb, and ZnO concentrations ranged from 50 to 1000 ppb under dark conditions. E. coli samples were enumerated over a 72-h period. The results demonstrate that both NP and bacterial concentration significantly influenced outcomes. For example, 10 ppb AgNP alone did not achieve any disinfection under any bacterial loading over 72 h. However, log removal values (LRVs) of − 0.86, − 1.06, and + 0.01 were measured in water with 102, 103, and 105 CFU/mL, respectively, when combined with 75 ppb ZnO and − 2.62, − 2.17, and − 3.06 when combined with 1000 ppb ZnO, respectively; a negative LRV indicates bacterial inhibition, while a positive LRV indicates bacterial growth. This study therefore illustrates that co-application of AgNP-ZnO holds potential for implementation in the design of low-cost water treatment solutions that utilize nanoparticles for disinfection if influent bacterial concentrations are managed appropriately.

Robbie A. Venis, Chaitanya Luhar, Onita D. Basu
Long-Term Community Engagement and Participatory Education for Improving Water and Health Outcomes: A Case Study in Rural Tanzania

Progress toward Sustainable Development Goal 6.1, universal safe drinking water access, has been slow, raising important questions regarding the present methodological paradigm (UN, in Sustainable Development Goals Report, United Nations, Geneva, 2021). For instance, Martin et al. (Tropical Med Int Health 23:122–135, 2018) found 65–95% of drinking water interventions in rural areas failed to realize their intended results within 6 months of implementation, contributing to systemic marginalization of populations in these geographies. Reform of sectoral practices in engaging communities and promoting sustainable water, sanitation, and hygiene (WaSH) is therefore in order. This research responsively investigates localized and participatory intervention planning and education methods, combined with regular interfacing between implementers and participants, as a mechanism for improving long-term water-related health. Multi-year consultations in rural Tanzania combined key informant interviews, focus groups, and observational learning to develop a 14-week (3-month) participatory WaSH education program among Maasai women. Ceramic water filters were provided for home-use and diarrheal outcomes among the participants, and their children were recorded regularly over an 18-month evaluation period. Educational lessons were also thrice repeated at baseline, 9 months, and 15 months. Initially, the percentage of the group reporting monthly diarrhea decreased from 38% at baseline to 8% at the 3-month mark, increasing to 32% at the 6-month reporting time after educational lessons were paused. After education restarted at 9 months, 0% reported diarrhea at the 12-month mark. Reported diarrhea then increased to 5% after a second pause in programming at 15 months, decreasing to 3% at 18 months after the third set of educational lessons. Additionally, less filters broke during this program than was reported in literature (Brown in Ceramic Filters for Point of Use Drinking Water Treatment in Rural Cambodia: Independent Appraisal of Interventions from 2002–2005, 2007). The intervention therefore showed a positive correlation between education provision, health, and filter care illustrating how locally relevant education may facilitate water technology uptake, and that regular interfacing between implementers and participants is critical to addressing long-term water access.

Robbie A. Venis, Onita D. Basu
Integration of Remote Sensing, MCDM, and GIS Network Analysis to Better Locate Waste Treatment and Processing Facilities in Saskatchewan, Canada, at a Regional Level

A framework for landfill site suitability evaluation is developed in the current study by integration of remote sensing, MCDM tools, and GIS network analysis. Saskatchewan is selected as a study area to evaluate the outcomes of this framework regarding the presence of remote communities, the scattered pattern of population distribution, and the acceptance of regional and innovative solutions for solid waste management at a provincial level. Results indicate an abundance number of suitable areas in the southern and central parts of the province for future landfills, probably due to dominant forest areas and frequent water bodies in northern regions. Over 43% of the potentially suitable sites for landfilling have access to the neighboring population centers, while some northern and central remote communities are without access to proper landfill sites. Thus, adopting less suitable sites for landfilling and using long-distance traveling trucks for solid waste collection might be alternative ways to overcome this issue. Current framework not only indicates the suitable sites for future landfills but also accounts for population coverage and accessibility to different candidate sites. Additional constraints such as slope, aspect, presence of airports, soil types, and hazardous areas might be integrated to precisely define the location of future landfills.

Nima Karimi, Kelvin Tsun Wai Ng
Aggregation of Nighttime Light Imagery, Remote Sensing Indices, and Network Analysis to Detect Probable Illegal Dumpsites in Regina and Surrounding Areas

Illegal dumping activities are identified as a major global issue during recent years due to their adverse environmental and health impacts. The current study developed an illegal disposal site (IDS) identification algorithm by aggregating nighttime light (NTL) satellite imagery, remote sensing (RS) indices, and geographical information system (GIS) network analysis. This algorithm was applied in division no 6 in the province of Saskatchewan, Canada. Among all four detected potential IDS, three of them were located in the western edges of the city of Regina with an intensified road network and no landfills in the neighborhood. Travel time evaluation showed that no populated points are in the proximity of 15 min from the centroids of potential IDS. All IDS were laid over railway routes which connected the city of Regina and the northwestern, northeastern, and western areas. Potential IDS was also evaluated regarding the location of reserve lands. IDS site’s location analysis concerning neighboring populated points and reserve lands indicates that IDS 3 should be carefully monitored due to its potential environmental and health impacts. It is believed that higher travel times from populated points to IDS might reduce the risk of illegal dumping activities. Results of this study indicate that not only detection of IDS is important but also its accessibility and coverage by neighboring populated areas should be carefully considered.

Nima Karimi, Kelvin Tsun Wai Ng
Proceedings of the Canadian Society of Civil Engineering Annual Conference 2022
Rishi Gupta
Min Sun
Svetlana Brzev
M. Shahria Alam
Kelvin Tsun Wai Ng
Jianbing Li
Ashraf El Damatty
Clark Lim
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