Proceedings of the Canadian Society for Civil Engineering Annual Conference 2023, Volume 11

Past major earthquake events worldwide have shown significant economic and social losses to impacted communities. The assessment of potential losses is essential for the preparation of mitigation plans and emergency response measures toward improved seismic resiliency. Recent research has focused on the aspect of loss of functionality of buildings as a significant measure of seismic resilience. Several approaches are available for loss estimations including empirical and analytical methods with varying degrees of complexity. For the assessment of a large portfolio of buildings, there is a need for simplified and rapid tools that can be applied with reduced computational time. This paper presents a methodology for the assessment of expected earthquake-induced losses including direct economic losses and the loss of functionality of existing high-rise reinforced concrete shear wall buildings in Eastern Canada. The methodology consists of hazard analysis using response spectra compatible with the National Building Code of Canada hazard values, structural analysis using an iterative capacity spectrum method, damage analysis based on drift and acceleration fragility functions for structural and non-structural components, and loss analysis based on the correlation between predicted damage states and repair costs as well as the probability of loss of functionality. A comparison between expected losses for different seismic design levels according to the year of construction is presented and discussed.

This paper aims to evaluate the accuracy and efficiency of four uniaxial OpenSees material models, including Giuffré–Menegotto–Pinto, Ramberg–Osgood, Bouc–Wen, and updated Voce–Chaboche, in predicting cyclic inelastic response of hollow structural section braces used in steel concentrically braced frames. A fibre-based numerical model of two hollow structural section braces that have been experimentally tested is constructed and is used to evaluate the capability of these material models in predicting brace cyclic response. In particular, hysteresis response and out-of-plane lateral deformation of the braces are presented and interrogated. The results show a superior performance of the Giuffré-Menegotto-Pinto material model in predicting brace strain-hardening response, first buckling load, post-buckling response, and reloading stiffness. Furthermore, this material model requires a lower computational cost to perform nonlinear analysis.

Past research has shown that soft-story wood frame buildings are vulnerable to seismic damage and potentially collapse in high intensity events. For seismic resilience assessment of these structures, it is essential to classify damage states after an earthquake. This paper describes the formulation of a damage index (DI) for post-earthquake assessment of wood frame buildings with a soft and weak first story. The indices are applied to a wood frame building representative of buildings built prior to 1970 in California and the United States in general. Data from shake table tests of a four-story full-scale model building is used for correlating specific structural parameters with associated damage identifiers. The model building was subjected to ground motions with increasing intensities, and it experienced different levels of damage. The computed DI is used to define different damage states on global as well as component levels. The proposed framework is found useful for the determination of a wood building’s suitability for occupancy after a major seismic event.

Strong wood-frame shear walls comprising double-sided sheathing, small nail spacing, and continuous rod anchorage systems have recently attracted attention in high seismic regions such as Chile and New Zealand. Although a wide range of experimental research has been conducted on the lateral response of conventional high-capacity shear walls with discrete hold-downs, investigations on the lateral response of stronger wood-frame shear walls with continuous steel rods are quite limited. This paper presents a comprehensive study aimed to provide a better understanding of the response of such strong shear walls under very large lateral design loads (over 50 kN) in the context of the Canadian Standard (CSA O86-2019). The strength, stiffness, and lateral deflection of shear walls with discrete hold-downs and continuous steel rods were estimated using the design equations in the standard and compared with a wide range of test data reported in the literature. Comparative assessment of strong versus conventional shear walls showed that factored strength of shear walls was underestimated on average by 53% for strong shear walls with continuous steel rods. In terms of deflection, shear walls with continuous steel rods exhibited up to 23% less deflection compared to those with discrete hold-downs under the same lateral loads. Unlike conventional wood-frame shear walls, the CSA fourth-term deflection equation overpredicted the stiffness of some strong walls with special configurations. Although continuous rod hold-downs showed a significant effect on both maximum strength and initial stiffness of the strong shear walls examined in this study, further numerical studies validated by testing data are suggested to better understand the behaviour of strong shear walls in practice. Virtual testing of different wall configurations under seismic loads is recommended to optimize the design of cost-effective mid-rise wood-frame buildings in the future.

Advancements in technology have seen bridge owners progressively adopting the use of drones as an inspection tool of their structures. Although currently being used, it is believed that the full potential for drones has yet to be recognized and is not a common tool used by bridge inspectors today. The use of drones for enhanced bridge inspections is presented with recommended procedures to guide their use. The use of drones for bridge inspections is discussed. A comparison of two commercially available drones that offer a form of autonomous drone operation is presented. In the early stages of implementation, selected case studies on the use of artificial intelligence (AI) software for bridge inspections are reviewed. The use of 3D models is presented; however, the accuracy and reliability of using models for inspections are not discussed. The literature review includes a short summary of the Ontario Structure Inspection Manual (OSIM) guidelines. A review of the Canadian regulatory environment for drones is summarized for reader information. The benefits for Department of Transportations (DOT) of developing procedures for autonomous drone flights and using of AI software are discussed, and short to long-term recommendations are presented.

The recent changes of National Building Code of Canada and the International Building Code allow mass timber construction (MTC) represented by cross-laminated timber (CLT) to be used in buildings with taller heights, more stories, and greater allowable areas. These new changes in the building codes on both sides of the border would remove many hurdles in the jurisdiction level to promote the use of timber in mid-rise and high-rise buildings. As typical CLT buildings heavily rely on the connections from self-tapping screws (STS), structural behavior of these connections is important. This work reports the laboratory experiment of STS connections with steel side plates under monotonic and cyclic loadings. The goal of the work is to explore potential technology for CLT and other MTC to further exhibit strong and ductile behavior under disastrous loads. Five-ply CLT samples are used in the study, with their thickness of 175 mm. The STS from two manufacturers with the nominal diameter of 8 mm are tested for their shear capacity in CLT samples under monotonic and reversed cyclic loading. Eight replicates of each type of connections are performed to study their consistency of the results. The test results indicate that the screw connections can develop a mean ultimate strength of 25.6 kN for one pair of screws. The peak loads from the cyclic tests are similar to the monotonic ones. These cyclic test results indicate the great potential for energy dissipation under seismic loading. The peak load values have a low COV, which indicates that the results are very consistent. The ductility ratio is found to range between 1.59 and 2.10, depending on the screw types and the reference methods. The ductility ratio values have significant variations, represented by large COV values. The maximum strength and energy dissipation for each cycle are also reported. With these results, the parameters for hysteretic models can be obtained, which can be used to predict the performance of different configurations of STS connections. These parameters can also be used to explore the potential new applications in structural components with ductile structural response for gravity and lateral loads.

The randomness in material properties and degradation mechanisms in existing structures can be considered in structural safety evaluations using random fields. Random fields describe the spatial distribution of a given material property as a function of a predefined set of parameters. Incorporating random fields in nonlinear finite element (FE) simulation, referred to as stochastic FE method (SFEM), is hindered by the lack of practical computer tools that automate random field generation using commercial FE software. The objective of this research is to develop a novel framework and computer script to generate SFEM models using the renowned LS-DYNA FE software. The functionality of the computer script is demonstrated through an example involving SFEM simulations of a reinforced concrete caisson wharf segment subjected to mooring load. A reliability analysis is conducted using the obtained SFEM responses through Monte Carlo simulation. Analysis results indicated the viability of the computer script and the successful representation of random fields in LS-DYNA.

Out-of-plane (OOP) failure mechanism is a common collapse mode for unreinforced masonry walls in the lack of connections between structural members or when the wall cross-section is characterized by multiple leaves assembled without following the so-called rules of the art. Other factors influencing the OOP behavior are the transversal texture, presence of infill material, and mechanical properties of the constituent materials, i.e., unit and mortar joint mechanical properties. Furthermore, environmental conditions may negatively affect strength properties and cause aging and degradation. Currently, the main limitation of state-of-the-art tools stems from the practical difficulties of surveying the cross-section of historic masonry structures due to enormous costs and the limitations of performing destructive tests. Therefore, computational models should address the uncertainty in the material and geometrical properties to identify possible solutions for conserving historic masonry structures. This paper aims to determine the effect of cross-section geometrical morphology of unreinforced masonry walls. Throughout this study, a collection of masonry cross-sections is considered by different morphological properties, and their structural response is analyzed by performing pushover simulations with discrete element method (DEM). The effect of cross-section morphology on strength capacity and failure mechanism is critically discussed. Finally, a simple analytical equation is modified to take into account the imperfect connection of the masonry leaves.

For maintaining and prolonging the service life of civil constructions, structural damage must be closely monitored. Monitoring the incidence, formation, and spread of damage is crucial to ensuring a structure’s ongoing performance. To give realistic means for early warning against structural deterioration, numerous monitoring and detecting approaches have been developed, such as vibration-based techniques, machine learning (ML) and especially deep learning (DL) algorithms. In this paper, the effectiveness of a deep learning technique known as long short-term memory (LSTM) for detecting damage in a steel cantilevered I-beam using a model-based approach has been investigated. For this purpose, a finite element model of an undamaged I-beam and several cases of I-beams with different damage combinations were prepared. The LSTM model was trained with the acceleration response sampled at different points on the top flange along each I-beam. Also, random normal noise was added to the acceleration signals for considering the effect of noise in the data extraction process. In this study, damage was defined as openings in the beam for simulating the stiffness reduction in the beam. It was noticed that by using the acceleration response of just one point on the top flange, the trained LSTM model can distinguish the undamaged beam from the damaged one with high accuracy.

The integral abutment bridge concept allows removal of expansion joints, bearings, piles for horizontal earth loads, and other uneconomical details. These details not only add to construction costs but also increase the maintenance work and expenses. When expansion joints are eliminated from a bridge, thermal stresses must be accounted for in the design. This paper describes the design challenges for a 45.6 m one-span integral abutment bridge, nearby Gatineau, Quebec, Canada. According to the geotechnical report, the soil under the foundation of the bridge consists of a 1.0–5.4 m granular embankment mixed with organic material and layers of wood chips, 15 m layered deposits of granular and cohesive soils, and a 35.7 to 40.8 m thick clay that is laid on a till layer. Because a 5.3 m granular backfill of abutments would lead to remarkable consolidation settlement and maintenance issues, it was decided to substitute 3.7 m of the granular backfill with a lightweight material to minimize the long-term settlement problem. A 3D bridge model in CSiBridge was used to simulate the construction stages and nonlinear behavior of soil around the piles to predict the induced efforts in the bridge due to different loads, including thermal and deck shrinkage loads. Structural design of piles was accomplished by taking into account the plastic hinge at the top of the piles and estimating the buckling free length of piles based on analysis of pile under lateral load in L-PILE software. While some Canadian provinces have developed standard details for approach slab joints, Quebec’s ministry of transportation (MTQ) does not propose any standard expansion joint detail for integral bridges. Therefore, the typical strip seal expansion joints detail of MTQ was adapted for this project to reduce water infiltration inside the joint even though it is away from the deck and is located at the end of approach slab. During the construction, the result of test piles revealed that excess pore water pressure due to pile driving operation needs some time to disappear. Thus, minimum waiting times for the main stages of construction were defined.

Canada is beginning to follow the European trend of shifting toward the reuse of existing structures to reduce environmental impacts. This shift has created a new culture of structural conservation and the need for engineers to understand the procedure of structural assessment of existing buildings. Historical structures are a specific niche of existing structures that require a closer assessment. A historical structure should not be damaged during assessment and is defined as a building or group of buildings that has been formally recognized for its esthetic, historic, scientific, cultural, social, or spiritual importance or significance for past, present, and future generations. The designation causes challenges in the testing available for data collection of material properties. Testing is limited to nondestructive (NDT) and minor destructive testing (MDT). Advances in technology have made nondestructive testing more reliable and easily accessible. Tests like laser scanning can map out the geometries of a structure, while ground penetrating radar (GPR) can confirm reinforcement details. NDTs are effective in confirming assumptions of structural properties and/or determining its material properties. Minor destructive testing relies on a sample of the structure to perform basic material property tests to gather information on strength, stiffness, and chemical microstructure. X-ray diffraction, scanning electron microscopy, Rockwell hardness testing, and tension/compression tests are all forms of MDT. The material properties determined from the above NDT and MDT can be used in finite element models (FEMs) to assess structural capacity. The FEMs allow engineers to determine possible failure modes of the structure and determine whether strengthening of members or buildings is required to increase the safety of the building. A case study was conducted to determine the material properties of the absorption building located in the historic Turner Valley Gas Plant (TVGP) in Alberta. The absorption building was constructed in the 1930s from structural steel piping and concrete. The NDT and MDT results were sufficient to determine the building’s material properties and eventually the structural capacity. The recommended NDT and MDT should be standardized to guide engineers when conducting structural assessments on historical structures.

Extreme wind events are becoming a higher risk within dense locations involving the newer generation of taller and slender structures. When tall structures are constructed in close proximity to one another, pounding of structures can transpire when subjected to such extreme lateral loading (e.g., wind or earthquakes) when the separation distance is insufficient. Damages from structures due to pounding can result, ranging from minor to major disasters, ensuing in a possibility of a total collapse. A separation distance between the interactive structures can be determined to mitigate a pounding event. This study focuses on developing a mathematical formulation through an optimization process to determine the required separation distance between two adjacent structures to mitigate wind-induced pounding. Next, the developed mathematical formulation will be further developed to determine the maximum pounding force of the two adjacent structures when the mitigation of a wind-induced pounding cannot be achieved. The study will first validate wind loads on two equal-height structures in proximity aided through large eddy simulations (LES). A finite element method (FEM) model is then used to validate the structure’s performance (i.e., deflections and pounding forces) from the captured wind loads. A genetic algorithm (GA) is utilized to develop the mathematical formula to estimate the required separation distance and maximum pounding force while optimizing the fitting parameters. Results show that taller structures are also more susceptible to more vital pounding forces when such structures become closer in proximity to one another. Contour plots were conducted which map the relationship between the mean wind velocity and natural frequency of the structures for the separation gap distance and the mean wind velocity and separation gap distance for the maximum pounding force.

Structural health monitoring (SHM) is a process where a system is monitored over time through periodically recorded system response measurements related to changes in material and geometric properties. SHM aims to provide accurate and just-in-time information concerning structural conditions and performance through the recording of representative parameters over the short or long term. A proper SHM system can give an owner better knowledge of the structural conditions in real time, facilitating a better-educated approach to planning maintenance activities which may prolong the structure’s service life beyond the design life, and decrease potential future major repair costs. Advances in structural monitoring enable the collection of large data sets from strain gauges for usable information. However, making sense of these data remains a challenge. In addition to complexities with working with time series data and considering seasonality effects, the sensors are exposed to harsh environmental conditions, which can impact the accuracy and validity of recorded results. In this research, data collected from a steel truss cantilever bridge in Canada, ON, were used as a case study to propose an automated workflow for sensor data outlier detection. Thirty-five (35) weldable strain gauges, having a nickel–chromium alloy grid encapsulated in fibreglass-reinforced epoxy phenolic, were placed along the bridge, where data were collected every one (1) minute for a two (2)-year period. Using Python3, input data were transformed into features for a fitted classification machine learning model to identify outlier periods. The results were cross-validated using a time series CV fold strategy to assess the model’s predictive power whilst also considering environmental effects. To perform SHM accurately, it is important to implement processes which can capture when there are anomalies in the sensor data quality. Ontario has over 15,500 bridges as of 2020, the most out of any province, with another ~ 500 bridge projects currently in construction. Statistical methods and machine learning algorithms can be applied to existing bridge sensor data to ensure that information is being delivered accurately, which can inform important decisions on cost and repair in an automated manner for engineers.

The variability in wood mechanical properties is one of the concerning factors when considering timber in structural applications. This variability is influenced by the presence of visible defects such as knots, grain deviations, and splits. Multiple models were developed to predict the mechanical performance of timber by means of visual stress grading. Stress modification factors are determined according to the frequency of knot sizes and slope of the grain within a certain stress grade of a wood species, to be applied on clear wood strength values for that species. The development of stress grades requires large surveys of knot properties and distribution within a timber species, where knot sizes on nominal dimension lumber faces are measured to develop knot data, and these data are used to determine the average sum of knot sizes in 1-foot lengths taken at 2-inch intervals on each timber board. According to the American standards, to develop a stress grade, physical mapping and measurements of knot data for at least 1000 linear foot of lumber should be done. Such exhaustive and time-consuming process can be automated by state-of-the-art computer vision and segmentation analysis techniques. Images are captured for pieces of lumber, and image adjustments are made to enhance contrast and emphasize features. Then, a first-order Gaussian derivative filter is applied on each picture to develop a binary contour image that contains the edge features of all knots. Those components formed by edge detection are then measured in pixels, where the nominal dimension of the lumber is used to set the scale for pixel dimensions to real-life dimensions conversion. This paper purposes a knot detection and segmentation algorithm for Casuarina glauca lumber, resulting in a fully automated knot data collection process.

Stadia and other gathering places are often built using long spans of lightweight truss systems that allow for unobstructed views. Due to these large open spaces and the structure often being built from steel trusses, fires within these spaces are often localized and the residual strengths of the damaged areas need to be immediately evaluated. These buildings are made to accommodate large events, such as concerts and sporting events, so when a fire occurs, the need for the evacuation of the entire space can be costly. One such example occurred at a sports event in 2022, when a speaker in the rafters caught on fire. The entire stadium was evacuated, resulting in a large financial loss as all tickets were refunded and broadcast suspended. The uncertainty in the residual condition of the structural system after a fire means there is a risk to the safety of occupants, and it takes time to assess the damage that occurred, both to the flame impinged truss and any adjoining system which may have taken additional load during the fire. It is therefore important to understand how a localized fire could impact common structural systems in stadiums. This would help address life safety concerns, while also lowering any financial impacts. This research herein aims to record the temperature distribution, using thermocouples, within a generic OWSJ when it is exposed to a known localized heat source. The potential for any heat shielding effect of the bottom chords of the OWSJ to the upper chords will be investigated using a 30-min methanol pool fire. This will provide the required raw data to validate modelling tools which can be used to analyze stadium structures during localized fire events, especially regarding their residual conditions afterwards. Guidance could therefore be generated using the results of this study to help practitioners determine post-fire conditions and the structures’ resiliency.

In Canada, there currently is a drive to rehabilitate existing buildings for new uses. This practice offers a way to reduce the environmental impact of construction by avoiding demolition and new construction while addressing the occupancy needs of today. One challenge of rehabilitating historic Canadian structures is to preserve the heritage value of their timber construction while also addressing concerns of fire safety. While contemporary timber construction only uses softwood, heritage structures often used hardwoods as well. The purpose of this study is to better understand the fire performance of these historic hardwoods for when they are encountered in practice. Historic hardwoods and softwoods were tested in a cone calorimeter following a modified ASTM 1354 procedure. The result of the testing found that the hardwood samples had a faster charring rate than the softwoods. This would suggest extra precautions are needed when working with historic hardwoods. This paper also evaluates the potential of using a numerical model for historic timber as a viable tool for evaluating the fire performance of heritage timber when suitable samples cannot be acquired for testing. The finite element analysis software, LS DYNA, was used. The hardwood tests were replicated, however, timber presents unique challenges as it is a combustible material, with complications regarding moisture and changing thermal properties with temperature. Results of the model indicate high char rates, nearly double the experimental results. One of the main challenges with the model is its inability to change the material from timber to char during pyrolysis. Therefore, the insulating char layer that would slow the rapid charring is not being accounted.

This paper aims to evaluate the capabilities of the eXtended finite element method (XFEM) against the finite element method (FEM) of damage modeling in predicting damage initiation and evolution in a tensile specimen. Although the comparison of the two mentioned techniques can be made for various specimens such as SENB, SENT, CT, and standard dog-bone specimens, a rectangular cuboid specimen made of API X65 pipeline steel with a through-thickness crack is modeled in the Abaqus finite element software in this work as a basic study. The maximum principal strain and fracture energy are respectively used as the damage initiation and evolution criteria in the initial stage of creating the XFEM model. The specimen then goes through a displacement-control loading at one end, while the other end is fixed until it fails. A similar procedure is followed for the FEM models working with either of the considered damage models in this study, namely the ductile damage model and the Johnson–Cook damage model, but with a contour integral crack so that the results of FEM could be compared with those of the XFEM. Mesh sensitivity analysis is also performed by considering different mesh types and sizes for the XFEM and FEM models.

The CSA S16 and the AISC 360 standards, and various bolt shear studies, are consistent in their assumption that a uniform distribution of applied force exists for short-bolted connections. However, a recent study at McGill University on conventionally constructed braced frames (CCBFs) reported that the shear force was distributed nonuniformly between the bolt group even though the connections were short. Based on this finding, a better understanding of the bolt force distribution and the unbuttoning phenomenon is needed, as they are key to accurately estimating the bolt group's shear strength. This was achieved by using the finite element (FE) method to prepare the tools needed to identify the failure mode occurring in a bolted connection, and to extract the bolt shear forces in a bolted connection. The behaviour of single-bolted connections subjected to shear loading was first studied using FE models to understand the components of shear resistance. Another goal of this study was to compare multiple extraction methods to obtain the bolt shear force and to determine the most accurate method. It was found that the total force in a bolted connection is being transferred in different mechanisms. These mechanisms included pure shear on the bolt, mechanical interlock between the bolt and plate, and friction between the plates. It was also found that using the contact method provides the most accurate estimate of the bolt shear force for a single-bolted connection. The behaviour of multi-bolted connections subjected to shear loading was also studied to assess how the extraction methods used for single-bolted connections could be applied. In addition, failure indicators to capture net section fracture and bolt shear fracture in FE models of the multi-bolted connections were investigated. It was shown that the equivalent plastic strain (PEEQ) could accurately predict the initial onset of net section fracture. In contrast, comparing the bolt's demand and capacity curve can accurately predict the bolt shear fracture. Moreover, it was shown that extracting the bolt forces from FE models is a complex procedure with various methods available.

Concrete beams reinforced with a combination of steel rebars and glass fiber-reinforced polymer (GFRP) rebars can offer enhanced ductility, serviceability, and durability compared to those reinforced with the same total number of steel or GFRP rebars. This paper presents the flexural and serviceability behavior of steel-GFRP hybrid reinforced concrete (RC) beams. A total of four reinforced concrete beams, including two control beams, one reinforced with steel rebars and one with GFRP bars, and two steel-GFRP hybrid beams were tested under a four-point bending setup. All the beams were reinforced with four 20 mm (No. 6) rebars placed in one layer. The ratio of GFRP to steel reinforcement was the main parameter investigated. The experimental results of the beams were analyzed and compared in terms of flexural capacity, yielding load, and deflection. Based on the experimental results, steel-GFRP hybrid RC beams exhibited a higher ultimate strength than the steel RC beam but a lower ultimate strength than the GFRP RC beam. Moreover, the deflection at the same load level increased by increasing the GFRP to steel reinforcement ratio in the cross section. In addition, the results showed that the GFRP to steel reinforcement ratio significantly affects the flexural behavior of hybrid RC beams. Finally, the moment capacity of the beams was calculated using the fundamentals of section analysis, which showed very good agreement with the experimental results.

This paper presents the mechanical analysis of fiber-reinforced polymer (FRP) pipes subjected to parallel plate loading through finite element (FE) simulation. The outcome was compared to results from an experimental test conducted on a set of glass FRP (GFRP) and carbon FRP (CFRP) pipes with approximately the same geometry. The simulation employed a displacement-controlled approach, aligning with the ASTM D2412-11 standard loading method employed in the experimental testing program. The modeled GFRP and CFRP pipes measured 315 mm in width, while their internal diameters were 330 mm and 336 mm, respectively. The pipes had an approximate thickness of 4 mm. The FE model accounted for large deformations, resulting in simulation outcomes that showcased increased pipe stiffness as the cross-sectional geometry changed from circular to elliptical under loading. This mechanical response was consistent with the behavior of FRP pipes observed in the experimental study. Upon validating the FE model, the simulation output provided additional data not captured experimentally, including stress changes at the failure region and stress propagation within the pipe's cross section.

Canada’s Wonderland (CW) is an amusement/theme park located in Vaughan, ON, Canada approximately 30 km north of downtown Toronto, ON. In 2011, CW retained R.V. Anderson Associates Limited (RVA) to provide consulting engineering services for the steel “giga-coaster” named Leviathan located within the Medieval Faire section of the park. Leviathan was designed by the Swiss firm Bolliger & Mabillard (B&M) as their first roller coaster to exceed a height of 91.5 m (300 ft). As of February 2023, Leviathan is the tallest and fastest roller coaster in Canada standing 93 m (306 ft) tall and reaching a top speed of 148 km/h (92 mph). Leviathan is also ranked as the seventh tallest and eighth fastest steel roller coaster in the world. RVA’s structural services included designing concrete foundations for the roller coaster columns. This paper summarizes how RVA designed the concrete foundations for the columns. Topics of discussion include the following: CW background; planning and theming; design and construction team; ride features; information gathering; definition of load cases; calculation of maximum design forces; design of concrete beams/slabs; design of concrete piers; and project milestones. In total, RVA designed 237 concrete piers to support track columns. This required over 2400 m3 of cast-in-place concrete. The largest and deepest piers were 1830 mm in diameter and 12 m deep, respectively. Due to high vertical and horizontal forces generated by train dynamics, some track columns required grade beams or slabs with multiple piers underneath. A significant pier design challenge was avoiding the below-grade artesian-like sand layer, which would have required more complex and costly construction means/methods. Construction was successfully completed in April 2012, and Leviathan has been operational ever since.

Wall-pier highway bridge is one major bridge type in seismic zones around the globe. Unlike well-designed bridge columns dominated by seismic flexural damage, pier walls in a bridge system exhibit unsymmetric and heterogeneous behaviour under seismic loading. In particular, they feature distinct seismic damage modes along the two principal axes, i.e. out-of-plane bending failure in the weak-axis direction versus in-plane shear failure in the strong-axis direction. Such a complex seismic behaviour is combined with the fact that earthquake ground excitations may cause the bridge pier wall to respond in any non-principal direction that couples out-of-plane bending with in-plane shear. Despite this complexity, seismic responses of highway bridges designed with pier walls have rarely been examined in the literature. This study fills the research gap by analysing the seismic performance of a wall-pier bridge using nonlinear time history analyses (NTHAs). A high-fidelity finite element model of the wall-pier bridge is developed using OpenSees, where modelling considerations for different bridge components are discussed in detail. Specifically, fibre-type displacement-based beam-column elements are utilised to simulate the bending and shear behaviour of the wall pier along the two principal directions. The effectiveness of using this modelling strategy is validated against previous experimental results. Besides, zero-length spring elements with various force–displacement constitutive models are used to capture the dynamic interplay of abutment components and bridge foundations. Representative ground motion records are selected to perform NTHAs on the numerical model of the bridge system. Finally, the time history force–displacement hysteretic responses of various bridge components are investigated, focusing on the pier wall performance along different response directions. This study lays a technical foundation for the earthquake engineering community to analyse, design, and protect wall-pier highway bridges against seismic hazards.

Reinforced angle brackets are commonly used as connectors in wood structures. These connectors are typically installed with ring shank nails or screws. This paper presents the experimental results of cross-laminated timber (CLT) connections which consist of reinforced angle brackets and heavy-duty screws. These screws are one of the stiffest and the strongest options for the fasteners which can be used with the reinforced angle brackets. However, this option has not been extensively studied by many scholars yet. Therefore, this paper contains detailed numerical simulations with aim to be able to predict the failure modes and the load-bearing capacities of experimentally tested connections. Benefits together with the limitations of the presented numerical method are discussed.

Wood-frame shear walls are known to be efficient and cost-effective structural systems in resisting lateral loads. Conventional shear walls with regular discrete hold-downs are often used in low-rise wood-frame buildings. However, in mid-rise buildings, shear walls with higher capacity are required to resist larger lateral forces. Previous research on high-capacity wood-frame shear walls has shown that the anchoring system has a significant effect on lateral displacement and stiffness of walls. Research on structural performance of high-capacity wood-frame shear walls (with different anchorage systems) is limited. Hence, development of new design recommendations of such systems has been increasingly sought after since the provisions in current North American cater to only conventional shear walls. In light of this, this research preformed a comprehensive survey and collected experimental data from previous research to examine the applicability of current design provisions on high-capacity shear walls with different configurations. For comparison purpose, conventional shear walls are also studied. The deflections of a range of walls with different hold-down systems were calculated based on the equations provided in the American Wood Council (AWC) 2021 Special Design Provisions for Wind and Seismic (SDPWS) and the Canadian Standard Association (CSA O86). The accuracy of each set of design equations was evaluated, and the validity range of such equations for different categories of walls including low-capacity and high-capacity walls was determined. According to this investigation, further research on high-capacity shear walls with continuous rod hold-downs is needed.

Volumetric modular building structures are becoming increasingly popular due to their significant advantages over traditional on-site construction in terms of speed, quality of workmanship, and environmental impacts. A common type of modular building structure consists of gravity-force-resisting steel modules laterally supported by precast or cast-in-situ reinforced concrete shear walls. This type of modular structural system is common in mid- and high-rise modular buildings. In this system, the shear walls are designed to resist 100% of the lateral loads, followed by designing the gravity-force-resisting modules to stay elastic or have the sufficient nonlinear capacity to support the gravity loads while undergoing earthquake-induced deformations. However, the steel modules inherently exhibit a certain amount of lateral rigidity intended to resist the handling and transportation loads, forming a hybrid system that inevitably attracts a fraction of the total lateral loads. This study examines the effects of three parameters on inter-story shear distribution between gravity-force-resisting modules and the reinforced concrete shear walls: (1) the partial rigidity of intra-module connections, (2) the rotational rigidity of the vertical component of the inter-module connection, and (3) the in-plane stiffness of discrete floor diaphragms. It was found that the proportion of inter-story shear in gravity-force-resisting modules can be minimized by adequately designing the three aforementioned components above.

Cross-laminated timber (CLT) is a panelized engineering wood product known for its strong and lightweight properties. Construction with CLT panels has been a growing trend to meet the low-carbon building alternatives. This study generates a reliable artificial neural networks (ANNs)-based model for estimating the flexural performance of CLT panels. Genetic algorithm (GA) with multilayer perceptron (MLP) was implemented on a dataset of CLT panels considering width, span length, thickness, bending, and shearing strength variables as input parameters to determine the flexural strength of the panels. 70% of the data were used for training and 30% for testing phases. The accuracy of GA-based MLP model was evaluated by comparing the results with multiple linear regression (MLR) and a variety of feed-forward (FF) models. The results revealed that the GA-optimized MLP model could estimate the flexural strength of CLT panels with the highest accuracy.

The Canadian Standards Association’s CSA A23.3:19 Design of Concrete Structures allows for evaluating the safety of existing structures based on analytical assessment or load testing. The latter is often favored by practitioners because the underlying concept is intuitive, so results are conclusive. The load testing procedures have the following shortcomings: (1) They do not provide insight on the actual load-carrying capacity, or how close the proof load was to the ultimate capacity of a structural component; (2) the proof load may cause irreversible structural damage, or even structural failure; and (3) many practitioners believe that a structure loaded to its nominal ultimate capacity typically engages alternate load paths to avoid failure, and that a different test result may occur under different environmental conditions. The goal of the present research is to model analytically the standard monotonic load test to assess the effectiveness of the acceptance criteria based on deflection recovery. Deficient members are represented using an effective mechanical reinforcement ratio, ω, less than the “expected” ω. Then, the total deflection of load-tested deficient members is evaluated based on a modified moment–curvature relationship that accounts for the effect of strain hardening of the reinforcing steel, and secondary and tertiary creep of concrete under high sustained loads. Residual deflections are obtained assuming the unloading is elastic. The results indicate that a limited range of deficient members can sustain the test load for 24 h without collapse, achieve a residual/total deflection ratio less than 40%, and so pass the load test. Thus, the link between structural capacity and deflection is tenuous at best.

Residual displacement of reinforced concrete (RC) structures can be utilized to assess their post-earthquake seismic performance. Earlier studies have focused on improving the post-earthquake functionality of RC walls by using re-centering devices or materials. Superelastic shape memory alloys (SE-SMA) have received considerable attention from the seismic community because of their appealing superelastic feature and good energy dissipation capacity. However, limited attempts have been focused on the investigation of their post-earthquake performance. This paper utilizes an approximate method recently proposed in the literature to estimate the residual drift demands at the end of the earthquake of SE-SMA RC walls. Additionally, new equations are proposed and validated before they are applied. To perform the evaluation, three SE-SMA RC walls assumed to be in a high seismic zone with different heights were analyzed and detailed according to current ACI-318 and ASCE7 codes. The results demonstrate the feasibility of the proposed equations to estimate residual displacement for rapid evaluation. Finally, based on a residual seismic capacity index (R) using proposed equations, a damage rating procedure is applied to determine specific damage levels of SE-SMA RC shear walls.

The use of glass fiber-reinforced polymer, GFRP, as an external reinforcement has increased considerably over the past few years and replaced as an alternative material to the steel rebar. Being lightweight, corrosion-free, superior tensile strength, and high mechanical performance makes it desirable for various applications. The leading advantage of using GFRP bars as a reinforcement is that it enables concrete structures to achieve long service life without any major maintenance. Installation of the GFRP bars is similar to steel rebars, but with less handling, transporting, and storage cost. However, concrete elements reinforced with GFRP bars have this potential to fail immediately after cracking, and therefore, the moment of resistance should be much greater than the cracking moment compared to the RC members reinforced with the steel rebars. This paper demonstrates the comparison between the results of using different grades of GFRP bars and steel rebars for precast concrete panels used as the facing of a mechanically stabilized earth (MSE) retaining walls. Then, the flexural behavior and modes of failure of these panels are investigated.

Controlling wind-induced load is crucial for low-rise building designs to achieve optimal resilience. A numerical approach using computational fluid dynamics (CFD) can be employed to assess the wind load during the initial stage of the design process, where a faster response can be secured, given the advancement in computational capacities over the past decades. Many factors, such as computational domain size and grid specifications, can influence the accuracy and efficiency of wind load evaluation using CFD simulations. This paper aims to examine CFD simulation’s efficiency and accuracy in wind load evaluation for low-rise buildings with gable roof geometry in two stages. The first stage will assess the impact of the computational domain size that involves the distances from the building to the boundary wall condition, which includes distances from the benchmark building to inflow, outflow, and no-slip walls. The second stage will investigate the impact of the computational domain discretization scheme, shape, and size. The study shows that computational domain size and discretization can be significant sources of error that can reach 29%, compromising the reliability of wind load predictions. The domain grid specification induced a considerable error of over 14%, precisely when tetrahedral grid shapes were used. The proposed recommendations introduce a practical approach to selecting domain size and discretization that can significantly impact the efficacy of computational wind load evaluation for low-rise building geometry.

This research investigates the influence of honeycomb orientation when used as a core component of sandwich beams. The parameter analysis included data obtained from eight sandwich beam sets tested in four-point bending conditions. The changing set parameters included the core thickness and facing components and the density of the core component. Initially, sandwich panels were fabricated in a wet layup process. The sets were cut into beams in two directions with respect to beam length; the beam length was 250 mm and held constant among the sets. The testing parameters—including the loading rate, fixture, and span—were also held constant. The research reports a change in both the top and bottom facing stress–strain rate, overall beam stiffness, and moment–curvature due to the change in honeycomb orientation during bending. Additionally, the change in ultimate failure mode among the sandwich beam sets has been reported. Results show the substantial influence of honeycomb orientation on the mechanical behavior of sandwich beams. The findings emphasize the need for careful consideration of honeycomb orientation in the design and evaluation of sandwich beams to optimize mechanical performance and guarantee safe utilization.

Many experimental and numerical studies have investigated the improvement in the seismic performance of reinforced masonry (RM) shear walls as a result of adding confined end zones (i.e., boundary elements) to rectangular shear walls. Moreover, the Canadian masonry design standard (CSA S304-14) introduced a ductile shear wall system and special seismic design provisions for masonry boundary elements. Furthermore, the National Building Code of Canada (NBCC, in National building code of Canada, National research council of Canada. NBCC, Ottawa [1]) permits the use of ductile shear walls as a seismic force-resisting system (SFRS) with height limits of up to 60 and 40 m for moderate and high seismic regions, respectively. Therefore, as a continuous improvement in the seismic design of RM structures, this study assesses the seismic performance of reinforced masonry core walls built up of RM shear walls with boundary elements to act as the main SFRS in typical RM buildings. The applied element method (AEM) implemented in the extreme loading for structures (ELS) software was utilized to simulate the seismic behavior of RM shear walls having different cross-sectional configurations and design parameters. Moreover, to evaluate the seismic performance of reinforced masonry core walls with boundary elements (RMCW+BEs). The results showed that RMCW+BEs can be used as an SFRS in RM structures and can be adopted in the next generation of North American masonry standards. Moreover, this study highlights the importance of implementing a shear amplification factor to account for the higher mode effects in multi-story RM buildings.

Degradation of traditional steel reinforcement in concrete used in bridge decks and barriers due to aggressive environments and use of de-icing salts in Canada has prompted a shift to using non-corrosive reinforcement materials in these applications. Non-corrosive reinforcement includes options such as stainless steel or glass fiber reinforced polymer (GFRP) bars. GFRP reinforced concrete bridge decks and barriers have become relatively popular in parts of eastern Canada but there are concerns in other regions about how these structures may be repaired if damaged by events such as vehicle impact. In this study the response of bridge deck-barrier systems reinforced with GFRP, steel reinforcement, and combinations of the two is investigated using an analytical approach. Barriers considered are single-slope TL-4 barriers commonly used for provincial highways in Alberta. Modeling is based on moment–curvature relationships, curvature integration to assess flexural deformation, bond-slip deformation/failure mechanisms, and shear failure mechanisms. As-built barriers constructed with steel or GFRP bars are considered and compared to repaired systems, consisting in saw-cut and doweled bars to create post-installed anchorage systems. Various anchorage bond-slip approaches are considered. The model is validated against previously tested concrete beams and tests on bridge barriers reinforced with steel or GFRP bars. A parametric study investigates the effects of bar material type (steel/GFRP), spacing, overhang length, and anchorage depth on the response of barrier-deck systems. Results show that though barrier capacity is reduced with the retrofitted processes, repaired barriers are still able to resist the expected factored design load for a TL-4 barrier per the Canadian Highway Bridge Design Code (CSA S6:19). Further validation and refining of this model, particularly bond-slip responses, is planned via an experimental program currently underway.

There is a growing awareness about the mental and physical well-being of people everywhere in Canada and for those living in relatively highly populated and polluted areas such as the Greater Toronto Area (GTA) in particular. The transportation projects continue providing venues for people to exercise and enjoy the stunning landscapes and natural sceneries all over the GTA. Herein, a high-profile arch/cable-stayed bridge over a flowing water stream is proposed to accommodate pedestrians and bikers while capturing the picturesque nature at a proposed park in the GTA. The bridge consists of a steel arch within the middle span that rises above the deck and is connected to the superstructure below with a series of cables. Toward the ends of the middle span, the arch extends gracefully below the deck to rest on the piers as end supports. The exterior spans are carried by steel girders and supported mainly by the substructure system (piers and abutments) while still connected to the arch for stability and controlling the arch buckling length. The utilization of corrosion-resistant materials and high-performance components, such as galvanized/sheathed cables and galvanized steel members, is considered. A sophisticated structural analysis is performed, using finite element modeling (FEM) to obtain precise figures of the straining actions and design demands, as well as representing the bridge construction stages. The most suitable design has been achieved while facing various challenges due to the complexity of the structural behavior during construction and thereafter. For comparison purposes, a simpler option of the concrete deck over variable depth steel girders is investigated. While the latter option presents favorable economic advantages, the arch/cable-stayed bridge is the recommended option as it offers the aesthetics level desired by the client and the public along with high sustainability and outstanding structural integrity.