Proceedings of the Canadian Society for Civil Engineering Annual Conference 2024, Volume 13

Concrete gravity dams built in the twentieth century has started to experience structural issues due to aging. Furthermore, rising water levels in reservoirs caused by climate change make dams more vulnerable. It is therefore necessary to develop effective methods to assess structural stability to facilitate analysis and decision-making. Several methods exist already to evaluate dam stability and to estimate ligament and cracking length at the dam-foundation interface, such as the load-increasing method and the strength reduction method. The load-increasing method involves raising the water level or increasing water density. The strength reduction method involves reducing the internal friction angle or reducing the cohesion at the dam-foundation interface. These methods are applied by incrementing the parameters of interest and by multiplying these parameters by a coefficient K to find the critical case when the sliding safety factor is equal to one or when the cracking at the base is significant to threaten the stability. To analyze these methods and their effectiveness, they are tested and compared on a 17.9 m high gravity dam using the gravity method for structural analysis. Some comparisons are made with the finite element method to highlight some limitation of the gravity method. The increasing water level method proves to be interesting, as it is relatively easy to apply. However, simplifying assumptions must be made for overtopping conditions. Results obtained when water density is incremented are not obvious, making this method not recommended. The strength reduction method gives good results and is easy to use.

In 2019, Ontario recorded 13,890 collisions between motor vehicles and fixed objects, resulting in 65 fatalities, 2174 injuries, and 11,651 instances of property damages. A significant concern arises from heavy vehicles veering off the road in high-speed environments, posing a substantial threat to overpass bridge structural safety. This study aims to examine the run-off-road (ROR) vehicle collision risks of highway bridge networks and to identify the critical bridges within the network. Currently, the scheduling of bridge maintenance and repair relies solely on the bridge condition rating system. While this system is beneficial, it does not account for the safety risks to bridges from extreme events, such as vehicular collisions, nor does it consider the broader implications of a bridge's functional loss on the transportation network. This study proposes a multiscale risk-based assessment framework to prioritize bridges for rehabilitation in response to ROR vehicle collisions. This framework assesses not only the probability of collision and the structural condition of individual bridges but also their criticality within the entire network. It incorporates multilevel criteria, including both component-level indices and network-level topology measures. Applying this framework to a highway bridge network in Ontario as a case study, the findings suggest that the overall bridge network faces a medium-to-low risk of collision. The bridges that feature high transportation criticality in the investigated network are generally in good condition and capable of withstanding potential vehicle collisions. The practical application of this study provides guidance for prioritizing maintenance efforts for highway bridges within budget constraints.

In precast construction, a building's structural integrity largely depends on the floor, usually composed of individual precast panels. These panels are typically connected along their length using mechanical connectors, which can experience significant residual deformations when subjected to seismic forces. These deformations can render the structure unrepairable. This paper aims to investigate the feasibility of using shape memory alloys (SMA) as connectors in precast concrete floors to enhance the earthquake resilience of precast structures. SMA connectors show promise due to their ability to withstand substantial deformations and return to their original state, thereby mitigating the large residual deformations associated with conventional steel connectors. This study modelled and analysed a precast structure under an earthquake ground motion obtained from the PEER Ground Motion Database to examine the seismic behaviour of SMA connectors compared to traditional steel connectors. Results of the numerical model show that the SMA connectors exhibit similar trends in relative shear and tension deformations at locations across the diaphragm but with magnitudes higher by 2–3 times. Following the seismic motion, the SMA connectors resulted in much reduced residual deformations than the case of steel connectors, with a reduction factor of up to 16.

The Boulevard des Galeries d’Anjou overpass is located over the metropolitan Highway 40 in Montreal. The bridge was built as a replacement of an existing three-span prestressed concrete deck bridge. The construction of the bridge in such urban area and over one of Canada’s busiest highways brought many design challenges and the necessity for use of innovative construction methods. It was demonstrated that the option of 61.2 m single-span bridge offered the best solution for both mobility in the area and future development needs. Thus, no long-term lane closures are required on Highway 40 during construction in addition to providing a wider vehicle space. The most restrictive design criterion was to provide 5.1 m vertical clearance as required by the provincial standards while the existing bridge had a vertical clearance of 4.6 m. Furthermore, the existing bridge has suffered from truck impact in the past years, and it was imperative to raise the new one. It was demonstrated that the design and construction of a conventional single-span bridge was not possible without the reconstruction of the existing approaches and the neighboring intersections in spite of having unsafe approaches’ slopes. To meet the geometrical criteria together with safe approaches’ slopes, the structure was designed and built using an innovative construction method which consisted of the use of a temporary support at the center of the bridge and temporary bearings at the abutments during the first stage of construction. Thus, the box girders of the superstructure were designed and constructed as two-span girders during the first construction stage until the deck slab was poured and reached the required resistance. Then, the temporary support was removed to obtain the single-span structure. This allowed to optimize the design and to have a thinner deck compared to the conventional single-span bridge. This paper will provide an insight on the design and construction challenges related to staging construction such as monitoring load distribution during the construction phases. The controlling of concrete temperature poured in cold weather conditions and cured under heated shelter will be also presented.

Stack pattern (SP) masonry construction is experiencing rising demand from homeowners, designers, and stakeholders, primarily due to its pleasing aesthetics. However, these stakeholders often lack awareness of the specific design constraints imposed on stack pattern reinforced concrete masonry walls by Canadian masonry design standards. In contrast, the American masonry code allows stack pattern masonry construction under certain conditions. This distinction in design standards significantly impacts the behaviour of stack pattern walls and is primarily informed by a single experimental study. To address the need for more comprehensive research on the performance of stack pattern construction and its counterpart, running bond (RB) construction, this experimental study was designed. Two reinforced concrete masonry walls each measures 4.0 m high × 2.4 m long × 0.2 m thick. These walls included 2–20 M vertical reinforcements spaced at 1200 mm and were constructed using both stack pattern and running bond methods. Subsequently, the walls were subjected to out-of-plane and constant axial loading. Additionally, ten concrete masonry prisms—five for each construction pattern were tested under monotonic compression loading. The results show that the flexural performance of stack pattern walls is 11% lower than that of their running bond counterparts. It can be found that both SP and RB walls exhibited similar failure modes but different out-of-plane displacement profiles. The results of this experimental study have the potential to influence the development of more adaptable Canadian masonry design standards and more stringent American masonry design codes, thus promoting harmonization between the two nations.

In order to predict the capacity of masonry shear walls, standards around the world normally have terms that account for contributions from the masonry, the axial load, and the horizontal reinforcement. The contributions from the masonry and the axial load are correlated with masonry shear strength, as proven by many researchers. However, several studies have shown that in one-course bond beams in partially grouted concrete masonry, the horizontal reinforcement does not carry load until after the masonry has cracked, so the horizontal bars did not contribute to the peak shear strength. To compare the accuracy of the standards, data for 125 partially grouted concrete masonry walls from tests reported in the literature were collected. The performance of the standards from Canada, Europe, and the United States in predicting the capacity is compared. Four recently proposed models from existing literature are also included as part of the comparison. Most of the existing equations overestimate the experimental testing results or have a large variation. Therefore, a model to predict masonry shear wall performance is also suggested to obtain more accurate results.

Masonry construction is a favorable alternative because of its robust thermal and acoustic properties, fire resistance, high load-bearing capacity, and minimal maintenance. However, traditional masonry construction requires specific on-site mixed mortar, a long construction time, and skilled masons. Several masonry construction systems, such as mortarless masonry, often called dry-stacked interlocking masonry (DSIM), have recently been introduced; these systems provide timely, efficient, and less costly construction. This paper briefly reviews the structural behavior of DSIM systems developed in different countries. The limitations of these studies, as well as the detailed classification of DSIM systems based on material, interlocking mechanism (i.e., projected nibs, dove-tailed lug, grout cores), alignment (running or stack bond), applicability to accommodate vertical and horizontal reinforcement, and block type (hollow or solid), are presented. In addition, the results of published experimental investigations evaluating the compressive strength and the in-plane and out-of-plane flexural behavior of DSIM walls are summarized. Analyzing the development of DSIM systems reveals the need for more structural efficiency of some types of interlocking masonry blocks due to the complexity of the block shape, which leads to misalignment during construction. The structural performance of all DSIM block types is affected by the block strength and interlocking mechanism in the horizontal and vertical directions. Interconnecting the cells with grout and reinforcement significantly increased the system strength and increased the initial stiffness. To develop design guidelines for DSIM systems for upcoming generations of masonry codes and standards, more comprehensive studies should be conducted to quantify the structural performance of each type of DSIM, especially their out-of-plane behavior and seismic response.

Canadian highway bridges are aging and giving rise to safety concerns. Frequent monitoring and significant investments are required to maintain their safety and serviceability levels. Corrosion of steel in reinforced concrete (RC) bridges leads to deterioration of materials, reduction of load-bearing capacity and increased maintenance costs. There is concern that climate change may further accelerate and amplify existing and new deficiencies alike, increasing the rate of corrosion and imposing new extreme loads on existing infrastructure. A now common technique for rehabilitation consists of externally bonded (EB) fibre-reinforced polymers (FRP) in critical locations of RC components to improve their overall structural performance. This technique has been shown to provide increased load-bearing capacity for damaged girders, however, there remains uncertainty related to their effectiveness when subjected to high environmental temperatures, especially when combined with corrosion damage. A two-span simply supported prestressed RC highway bridge was designed based on a review of existing bridges in Canada. A parametric study was conducted on this bridge to examine the effects of EB FRP rehabilitation on its performance when subjected to various levels of flexural reinforcement corrosion. The composite effects of heatwaves on the rehabilitated bridge were also investigated to assess their influence on the load-carrying capacity and serviceability levels. The study managed to quantify the ultimate strength and serviceability levels of EB FRP-strengthened bridges. This information will help determine the rehabilitation requirements of existing infrastructure, enabling adaptation to emerging challenges posed by climate change in the upcoming decades.

The serviceability limit state represented by the deflection control and cracking becomes important, especially for slender reinforced or prestressed fiber-reinforced-polymer (FRP) elements. Therefore, deflection under service loading conditions should be well-defined. No research has been conducted on the serviceability of rectangular concrete-filled FRP tube (CFFT) members with prestressing. This paper introduces a simplified method to calculate the short-term deflection of rectangular post-tensioned (PT) CFFT beams tested under four-point flexural loading. Based on a regression analysis of the experimental test results, a modified Branson’s effective moment of inertia (Ie) formula, which is employed by North American codes, is introduced to predict the (Ie) of rectangular PT CFFT beams at various loading stages. The proposed approach was found to be capable of predicting the moment-deflection response of the beams. The results show that the simplified approach yield conservative deflection estimates at the service load and equivalent load levels, with an average experimental-to-predicted deflection ratio of 1.21 ± 0.18 and 1.35 ± 0.19 and COVs of 15% and 14%, respectively.

Glass fiber-reinforced polymer (GFRP) bars are becoming more common in applications where corrosion resistance is desired, such as bridge decks and barriers. If retrofitting reinforced concrete with GFRP, or if adding a GFRP reinforced component to existing concrete, GFRP bars are often connected using adhesive anchors. In this process, a hole is drilled into concrete, adhesive (grout or epoxy common) placed in the hole, then GFRP bars inserted. Bond quality is often assessed using pullout tests on adhesively anchored bars. Though this test method is relatively easy to set up, results may not represent of stress states experienced in flexural members. Hinged beam tests are an accepted approach for developing bond-slip relationships used for design codes and standards for concrete reinforced with either steel or GFRP. A novel technique of fabricating hinge beam tests with adhesively anchored GFRP bars is presented in this study. This process involves casting a beam with a placeholder bar, removing that bar, drilling a hole for adhesive anchoring, then using a process analogous to grouting a post-tensioning duct to ensure that embedded bar length is sufficient. Trial processes showed that epoxy could flow around the bar without voids forming or leaking outside of the anchorage test region. Hinged beam tests on high modulus (60 GPa nominal stiffness) bars with 17.1 mm diameter GFRP bars bonded over an anchorage length of 225 mm with an epoxy adhesive were completed and compared to tests on the same bar without adhesive. Bars without the adhesive reached an average maximum bond strength of 12.1 MPa and failed at the interface between the GFRP bar coating and the core of the bar. Bars with epoxy adhesive reached an average bond strength of 11.2 MPa and failed at the interface between concrete and epoxy. Both types of bars were then successfully fit using the modified BPE model proposed by Consenza (1995) for GFRP bars in concrete. Results, including post-test inspections, show that the proposed technique was effective for assessing the bond-slip response of GFRP bars adhesively anchored to concrete.

In the field of structural blast engineering, understanding the interaction of blast waves with complex urban structures is crucial. Studies have explored how these waves behave in cityscapes, including phenomena like reflection, diffraction, and interactions between structures that affect the blast wave's propagation. A significant challenge remains in integrating these findings with dynamic structural load analysis, crucial for urban blast design. This study aims to analyze blast wave behaviors and overpressure profiles in urban settings which can lead to unique and intensified blast effects. Firstly, a qualitative computational fluid dynamics-based investigation of the 2020 Nashville explosion, caused by a vehicle-borne improvised explosive device in a dense commercial district, was presented to demonstrate complex wave patterns in urban explosions. Secondly, a parametric study extending from this event was conducted to quantitatively elicit nonconventional blast loading patterns and load profiles on building surfaces considering different charge placements. This comprehensive approach seeks to expand on the understanding of blast loading on urban structures and its comparison to traditional scenarios to highlight the importance of dedicated blast quantification in urban protective building design.

Concrete block masonry stands as one of the most prevalent structural materials in both Quebec and across Canada with many applications to loadbearing elements in residential, commercial, and industry low-to-mid-rise buildings. In this paper, mechanical testing done at McGill University investigates some critical aspects related to the compressive behavior of concrete block masonry that are still under-researched, specifically the bond pattern and size effects, as well as their combination, leveraging modern field deformation measurements applied to experimental tests. In current construction, stack bond emerges as the second most popular choice after the running bond for concrete masonry units. Despite the behaviors and deformations of assemblies built with either stack or running bond patterns tend to differ when subjected to uniaxial compression loading, limited data is presently available on this aspect and the combined aspect ratio effects. With respect to size effect, limited data exists on the impact of the height-to-width ratio on compressive strength, albeit CSA-S304-14, Table D.1 provides some guidance, offering universal correction factors for same-bond masonry specimens. Secondly, the CSA mandates the use of running bond prisms to represent characteristics under uniaxial compression testing, a practice seldom implemented in labs. This research addresses the knowledge gaps mentioned above through laboratory experiments, testing a total of 56 different assemblies under uniaxial monotonic compression loading, with unit and mortar testing to enhance data correlation. Preliminary findings suggest that stack bond assemblies, on average, demonstrated a compressive strength up to 15% greater than their running bond counterparts. Additionally, concerning the size effect, results for stack bond assemblies align with CSA standards, while for running bond assemblies, our tests indicate the need for a smaller correction factor.

This study investigates the seismic response of a concrete water reservoir subjected to the Northridge 1994 earthquake to identify the most critical locations for structural health monitoring of the reservoir based on the maximum deformation induced by the seismic load. The analysis employs a liner dynamic time history approach to assess the maximum deflection and stresses of the reservoir in two distinct scenarios: (i) empty and (ii) full water. The fluid–structure interaction is modeled using the finite element (FE) software, ANSYS©. Results demonstrate the developed model could be employed as a tool to conduct time history analysis and predict the transient response of the reservoir under seismic loads. Consequently, potential locations for installing structural health monitoring sensors could be identified based on analysis results.

The integration of Machine Learning (ML) techniques, particularly Deep Learning (DL) models, within Structural Health Monitoring (SHM) has expanded exponentially in the past couple of decades. Though significant advancements have been made concerning the adaptability of these technologies to SHM, DL-driven methods still face current, long-standing challenges within this domain. The availability and size of existing training datasets for SHM applications remain relatively restrictive creating difficulties in training new DL models which require a significant number of samples. Furthermore, these training datasets remain largely unbalanced, with the majority class belonging to undamaged structures, resulting in models that are biased toward the dominant class of damaged structures. As such, to address the data scarcity, and class imbalance issues of the SHM domain, few-shot learning (FSL) models have been explored in this study. Contrasting traditional ML methods, these models attempt to optimize the data versus accuracy problem by developing models that have significantly high accuracy while using a significantly smaller training sample size. In this paper, a prototypical network is proposed for the classification of structural damages of concrete and asphalt surfaces using limited data. The performance of each model is explored for low-sample environments, including 1, 2, 5, 10, and 20 images per class. Additionally, the performance of this FSL model is explored for different image transformation techniques, including histogram equalization, logarithmic transform, power transform, and phase stretch transform. Finally, the impact of the aforementioned image transformations is investigated to reduce the overfitting of inter-material datasets (datasets originating from different material types).

Previous research studies have been conducted to investigate the seismic behavior of Controlled Rocking Masonry Walls (CRMWs) that rely on gravity loads for self-centering and incorporate supplementary Energy Dissipation (ED) devices for response control (ED-CRMWs). However, these studies have highlighted several limitations arising from the installation of ED devices within the wall, with other challenges for repairs after the device yielding or fracturing. Consequently, a novel system known as Controlled Rocking Masonry Walls with Energy Dissipation Accessible in a Steel Base (EASt-CRMWs) was recently introduced. In this system, masonry walls are built on a steel rocking base, allowing for the installation of ED devices within the wall’s footprint. Furthermore, these ED devices take the form of externally mounted cantilevered steel flexural yielding arms, which can be easily replaced following seismic events. Although EASt-CRMWs have shown superior seismic performance when tested under cyclic loading, the dynamic response of this new system has not been explored to date. In this respect, the current study presents the experimental results of one EASt-CRMW that was subjected to snap-back testing followed by displacement-controlled quasi-static cyclic fully reversed loading. The experimental results are detailed in terms of the free vibration response decay, coefficient of restitution, equivalent viscous damping, force–displacement responses, and residual drift ratios. Based on these experimental results, the current study is expected to present EASt-CRMW as a resilient seismic force-resisting system within masonry construction, characterized by low damage and rapid recovery after major earthquakes.

A significant portion of the existing infrastructure, including bridges and buildings, is reaching the end of its operational lifespan due to aging, heightened operational demands, and challenging weather conditions. Considering these circumstances, it becomes imperative to conduct periodic inspections of bridges. In the realm of Structural Health Monitoring (SHM), conventional inspection methods face challenges of high costs, time inefficiencies, and safety risks for inspectors. This paper introduces an innovative approach that leverages Augmented Reality (AR) and Artificial Intelligence (AI) to redefine the landscape of structural inspections. The proposed system eliminates the need for heavy and expensive equipment, presenting a safer and more cost-effective alternative. With the integration of AR technology, inspectors can remotely assess bridge conditions without physical presence in hazardous or inaccessible areas. The system employs a machine learning model, capable of detecting and classifying multiple types of damage, including cracks and spalling. The simplicity and efficiency of the approach not only streamlines the inspection process but also substantially reduces associated costs. Furthermore, the system goes beyond detection by quantifying the length, area, and perimeter of identified damage, offering a comprehensive understanding of damage severity. This combination of AR and AI not only revolutionizes bridge inspections but also represents a paradigm shift toward a safer, more cost-effective, and efficient monitoring methodology. The potential impact on industry practices and inspector safety underscores the significance of the approach in the field of SHM. This paper presents results collected from a field test conducted on a full-scale bridge in Ontario. These results conclude that the system successfully detects cracks and spalling and quantifies their severity.

Structural element fabrication using direct energy deposition, specifically using wire arc additive manufacturing (WAAM) methods, is an emerging technology being explored by many industries. The ability to produce complex shapes while achieving high cost-effectiveness and scalability has received notable attention given the increasing demands of the structural steel fabrication industry. Moreover, the introduction of automation in the additive manufacturing (AM) process by robotically producing the elements using gas-metal arc welding (GMAAM) holds promise to enhance the constructability of structural steel products. Despite abundant research conducted on small-scale metallic AM products, the production of large-scale ferritic components on a scale suitable for civil engineering applications using GMAAM introduces new process variables and structural integrity challenges. This brings forth uncertainties regarding the GMAAM material and its performance such as: How do GMAAM materials perform in cyclic loading in comparison with the traditional product forms and welded connections (as per CSA W59)? And how do internal voids or defects within the GMAAM products affect the fracture toughness? Furthermore, the lack of standardization of AM technology in terms of manufacturing guidelines and practices is another major challenge that is yet to be tackled. As a first step towards addressing these issues, the current paper presents recent tests on GMAAM material samples to better understand the static properties, impact toughness, and fatigue crack propagation behaviour of these materials.

In this paper, a previously developed probabilistic fracture mechanics model—based on the Eurocode fracture mechanics design method—is used to assess the effects of climate, traffic conditions, and bridge configuration on the probability of failure by brittle fracture of Canadian highway bridges. The purpose of this assessment is to determine the relative importance of these parameters and provide insight that may be relevant if this model were to be used to calibrate the toughness requirements for the design of new steel highway bridges. Based on the presented analysis, it is concluded that the effect of the bridge location is relatively small, when three locations in each of Canada’s two climate zones are compared. The influence of traffic volume on the probability of failure by brittle fracture for average daily truck traffic (ADTT) volumes between 50 and 4000 trucks is also found to be relatively small. Similarly, bridge span and influence line are found to be relatively unimportant. Of the parameters investigated, the most important one is the effect of multiple vehicle presence (i.e., simultaneous truck crossing), which is found to be potentially significant when high traffic flow rates on long bridge spans are simulated.

Since calculating the fire resistance of reinforced concrete (RC) columns is a computationally expensive procedure and, in general, requires specialty software as well as knowledge of heat transfer principles, there is a need for accurate, simplified methods that can be easily understood and applied. Over the years, many simplified methods have been proposed to assess the capacity of RC columns during fire exposure. In this paper, nine of the available simplified methods are first summarized. Then, their utilization to estimate the capacity of columns, which were experimentally tested by others, was examined. Five methods were found to have comparable, reasonably accurate predictions. Two of them were more suitable for design due to their ease of implementation.

In steel structures, the connections within the joints are idealized as either rigid or pinned. However, the rigid connections have a point of flexibility, whereas pinned connections have some stiffness. Connection stiffness features a considerable effect on forces developed within the frame members, lateral displacements of joints as well as base shear of the structure during seismic events. In this paper, the influence of the semirigid (SR) behavior of the beam–column connection in the response of the frame structure is studied. The moment–rotation (M-θ) relationship is an important measure of the semirigidity of the connections. The SR connections are modeled as multilinear plastic (MLP) link elements with kinematic hysteresis behavior in SAP2000. A five-story steel special moment-resisting frame (SMRF) is modeled considering fully rigid (FR) connections as well as SR connections. The performance of the frame is analyzed using pushover analysis, and response parameters like time period, lateral displacements, base shear, and inter-story drift ratio are compared for rigid and SR connections. The semirigidity of the connection was found to increase lateral displacements of the modeled frame. Apart from this, the base shear also decreases in SR frames as compared to FR frames.

Present Canadian design standards for steel members prescribe a member slenderness limit of 200 for compression members and 300 for tension members to guard, in part, against excessive vibrations. The different threshold limits in both types of members reflect the fact that compressive forces tend to lower the natural frequency of members while tensile forces tend to increase it. The stepwise threshold slenderness limits presently provided in standards, while recognizing the influence of the type of axial force on the natural frequency of the member, do not reflect the effect of axial force magnitude within the member. Within this context, the present study aims to present slenderness limits for axially loaded members associated with a more consistent serviceability criterion based on the natural vibration, which reflects the level of axial loading. Toward this goal, a parametric study is conducted on compressive and tensile members with doubly symmetric cross sections by (a) developing a shell finite element model in Abaqus based on stressed eigenvalue natural vibration analysis and (b) closed-form analytical solutions. The study examines the effect of cross-sectional geometry, axial load level, and connection details on the natural frequencies of axially loaded members and proposes slenderness limits aimed to control excessive vibrations under human activity.

The seismic design of tall mass timber building systems has forced practitioners to look into high-performance alternatives. In practice, conventional platform-type CLT walls with light metal connections among each wall segment, well known for prefabricated low-rise construction, are substituted by cantilevered CLT balloon-type elements jointed to ductile steel components or dampers. In these systems, timber joints are designed to provide buildings with minimum damage and replacement of the dissipation devices can be done swiftly. This paper studies the behavior of a novel hybrid connector, made of steel rod and epoxy-based grout, for hold-down joints in CLT balloon-type assemblies. From the mechanics of materials to the lateral response of a modular wall, the paper provides specific individual properties required per the design of resilient structures. Material tests provided a robust dataset for clear wood and epoxy-based grout. Structural performance parameters of hybrid connectors, namely the elastic stiffness, yield capacity, and ultimate capacity, are also evaluated via testing. A 3D finite-elements (FE) model has been developed as an aid for simulating the behavior of the novel hybrid connector. This FE model has been further used to analyze the performance of a CLT balloon-type shear wall. The results from the testing on connectors show that the diameter of the rod and grout significantly influence the performance parameters of connectors. The quasi-static cyclic simulation on a CLT balloon-type shear wall showed that the wall is able to stand a drift of 3% without experiencing permanent deformation or loss of stiffness and strength in the connections.

The Markov chain (MC) model has been widely used for predicting deterioration of bridges around the world. The main component of the MC model is a transition probability matrix, which can be used to determine the probability of a bridge being in each of a set of condition states in the future based on its current condition state. Accurate definition of this matrix is therefore vital for ensuring good performance of the MC model. The maximum-likelihood estimation method (MLE) along with actual inspection data can be employed to determine this transition matrix. This study first goes over the MLE method for the determination of the Markov transition matrix. Following that, Markov transition matrices for six different US states, namely, Texas, Georgia, Mississippi, New York, Ohio, and Wisconsin were determined using the MLE method and bridge inspection data. In the end, the times to reach each condition state were determined for the concrete bridge decks in each location. This study shows that the concrete deck service life in the northern states with cold climates is significantly lower than that in the three states in the south with warm climates.

This article assesses the novel seismic stability provisions proposed for the Commentary of the Canadian Steel Design Standard CSA S16:24 to enhance the seismic stability performance of steel buildings and replace the classic strength amplification approach. They mitigate inelastic drift concentrations over the building height and reduce residual drifts. They also allow for the relaxation of existing stringent height limitations. The provisions stipulate that the seismic force-resisting system is required to develop a specified minimum positive post-elastic lateral storey shear stiffness and maintain this stiffness for a storey drift of at least 2.5% of the storey height. Extensive validations of this proposed new approach have been carried out, including on eccentrically, buckling-restrained, and friction-braced frames, to assess their effectiveness. This study focuses on nonlinear response history analysis of 10- and 20-storey eccentrically and buckling-restrained steel-braced frames in Vancouver, BC. It compares two approaches: one following the classic strength amplification approach, as prescribed in the CSA S16:19, ignoring the height limitations and another incorporating the newly proposed provisions for the CSA S16:24 Commentary. Results indicate that while the currently used approach of amplifying the yielding strength is inefficient in mitigating soft-storey response and collapse by dynamic instability when ignoring the height limitation, the proposed method effectively ensures stable inelastic response with uniform storey drifts and with reduced residual storey drifts across the studied building heights.

Across- and torsional-aerodynamic wind loads on buildings are complex phenomena to predict analytically. Existing prediction equations in building codes and literature were empirically developed based on wind tunnel tests. These tests only considered tall buildings constructed with conventional materials such as concrete and steel due to the assumption that the design of mid-rise buildings is not governed by across- and torsional-wind loads. However, tall mass timber buildings with heights equivalent to mid-rise concrete and steel buildings are prone to wind-induced oscillations because of their lightweight and low lateral stiffness. Hence, designers need to ensure that across-wind and torsional responses are controlled to uphold occupants’ comfort and maintain building serviceability. The existing empirical across and torsional-wind load prediction equations may not be applicable to tall mass timber buildings due to the height ranges considered in their development. In this paper, we first assessed the applicability of the existing equations by comparing their prediction with wind tunnel test data representing the height and plan aspect ratios of tall mass timber buildings. Significant discrepancies are observed in the predicted and experimental across-wind forces and torsional moment coefficients. The mismatches are more pronounced for buildings shorter than 96 m in height and those with large side ratios. Therefore, new semi-empirical equations are developed based on 18 wind tunnel experiment datasets. Comparisons between the proposed equations and experimental data demonstrate an improved match. The newly proposed equations provide a reference for the preliminary structural design of wind-excited tall mass timber buildings.

The tall building conceptual design phase is typically a time-consuming trial-and-error procedure that does not usually guarantee an optimal solution. An efficient optimization framework can be used to address complex challenges in layout planning. Yet the objective function evaluation process is computationally expensive, especially in cases where thousands of combinations of possible solutions should be investigated or time history analysis is required, as is the case in tall buildings with shear wall layouts. This conference paper presents a comprehensive comparative study on utilizing machine learning-based surrogate models within layout optimization frameworks for tall buildings. The focus is on evaluating the performance of various machine learning techniques in enhancing the efficiency and accuracy of layout optimization processes. The study explores the application of surrogate models, including random forests, support vector machines, Gaussian process regression, decision trees, and deep neural networks as crucial components of optimization frameworks. Each model is assessed for its ability to approximate the complex relationships governing shear wall layouts, which are crucial in resisting lateral loads in tall structures. The evaluation considers factors such as computational efficiency, predictive accuracy, and generalization capabilities across diverse design scenarios. The training samples are prepared using finite element analysis of multiple layouts based on the Latin-Hypercube sampling technique. This paper will focus on dynamic wind excitation, aiming to provide valuable insights into the strengths and limitations of different surrogate models, aiding structural engineers and architects in informed decision-making during the conceptual design phase.

Wood utility poles are widely used to support electrical cables in transmission and distribution networks in North America. Inspection and assessment of wood pole condition are largely based on manual methods, which are costly and inefficient in a large network. This paper presents an innovative solution to this problem by introducing a machine learning (ML)-based assessment tool to forecast the future condition of wood poles. The proposed approach uses the Random Forest (RF) algorithm, which achieves 91% accuracy in predicting the pole condition state. This study highlights the potential of ML in enhancing the reliability and cost-effectiveness of utility network maintenance.

A utility pole is a post used to support various utilities such as electrical cables, fiber optic cables, and related equipment. These poles are usually tapered, circular wood columns. Current design methods do not consider the effect of High Intensity Wind (HIW) events, such as downbursts and tornadoes, on these structures. The aim of the current study is to develop a simplified design method for these poles under downbursts and tornadoes. The effect of downbursts and tornadoes on the stress profile of 73 different utility poles is considered. The uniform profile that leads to the same maximum stress is calculated. Another important effect that needs to be taken into consideration is the secondary moment effect. Therefore, the uniform profile that leads to the same maximum deflection of the pole is also calculated for all these 73 case study poles. It is revealed that the pole’s height is the main pole parameter that causes a change in the equivalent uniform velocity profile value.

This research investigates the effects of freeze-thaw cycles on a specially designed concrete cube embedded with sensors. Over a six-year period, the cube (of volume 8 ft3) underwent over one hundred freeze-thaw cycles, which were monitored utilizing a combination of four Ultrasonic Pulse Velocity (UPV) pairs and fifteen temperature thermistors. The primary objective was to evaluate sensor longevity under repetitive freeze-thaw conditions, while a secondary goal involved a detailed analysis of irreversible effects on the concrete's UPV response. The concrete cube sample was produced six years ago under a Small Modular Reactor (SMR) R&D project. Initial freeze-thaw cycling was performed in the first two years, under natural environmental conditions, by periodically moving the cube outside and inside the laboratory (two cycles of freeze-thaw per week) during the period from November to April. The cube then sat idle for two years, and freeze-thaw cycles recommenced thereafter in an industrial freezer. The analysis methodology involved UPV waveform envelope amplitude, duration, and transit time calculations, with a thorough approach to normalizing data due to instrumentation changes. Challenges in the analysis process, including waveform anomalies and signal errors, are being addressed. The findings not only highlight the scientific rigor applied to the investigation but also emphasize the need for a comprehensive analysis of the embedded UPV sensors’ response in concrete under diverse freeze-thaw conditions.

Base isolation is a widely employed technique in earthquake engineering aimed at safeguarding structures from seismic damage by isolating them from the ground through specialized isolators. These isolators experience significant deformations during earthquakes, dissipating a substantial portion of the seismic energy and enabling the superstructure to behave as a linear, rigid body. However, this increased deformation necessitates specific demands on isolator dimensions and seismic gap, which can be challenging to accommodate utilities near the isolation layer. To address these challenges, additional devices can be introduced into base-isolated structures (BISs) to mitigate lateral displacements. One such device is an inerter, which is a passive mechanical device, and when paired with base isolators, it enhances seismic energy dissipation and reduces structural response, improving earthquake resilience. While numerous studies have validated the enhanced seismic performance of BISs equipped with inerters, limited experimental studies have been conducted due to the challenges involved in constructing BISs for experimental purposes. To address this gap, an experimental study through real-time hybrid simulation (RTHS) was conducted to evaluate the performance of inerters in reducing seismic demands on a BIS. A nine-story steel frame benchmark building is retrofitted to become a BIS with lead rubber bearings (LRBs), which serves as the numerical substructure. The inerter device paired with the LRBs is the gyro-mass damper (GMD) acting as the experimental substructure. The results obtained through RTHSs demonstrate that the incorporation of GMDs enhances the seismic performance of the BIS by reducing maximum story displacement, interstory drift ratios, and base shear.

The accurate determination of dynamic load effects is crucial for designing and assessing bridges, especially considering the increasing number of deteriorating bridges and ongoing construction projects. These effects are integrated into design through the Dynamic Amplification Factor (DAF), a ratio of the structure's dynamic response to its static response. DAF is influenced by various factors, including bridge length, road profile, traffic density, and vehicle-bridge interaction. This paper provides a comprehensive review of the available DAF models for bridges. While previous studies have focused on complex models to determine DAF accurately, this paper explores simple analytical models and assesses their applicability. Based on that, one of the selected simple models is then utilized to evaluate its comparability with dynamic load test results. The analysis demonstrates comparable results, suggesting that simple analytical models could provide valuable insights into the dynamic amplification of traffic loads on bridges. However, the performance of such simple models needs to be enhanced by incorporating additional bridge parameters, such as road surface irregularities and vehicle-specific factors like axle hop or body bounce frequencies.

While various non-destructive techniques are being increasingly adopted for comprehensive condition assessment, Ground Penetrating Radar (GPR) is recommended for bridge evaluation due to its distinct advantages of identifying major subsurface defects rapidly. The interpretation of data obtained from GPR profiles is a major issue for bridge inspectors due to the difficulty in correlating with the actual condition. The commonly utilized amplitude-based approach yields results that are not always reliable, as it ignores most of the information contained within a GPR profile. A novel approach based on image-based analysis involves an experienced analyst reviewing the GPR profiles and marking attenuated areas across them while considering the structural and surface anomalies, and other several parameters. However, this approach is rather subjective, can be time-consuming, and is dependent on the level of knowledge of the analyst. To address these shortcomings, the proposed generalized framework leverages the benefits of engineering judgment derived from image-based analysis by incorporating user-assisted input. The process involves the following steps: (a) user-input for the element being inspected to determine optimal clusters; (b) automated detection of hyperbolic regions using machine learning or deep learning methods; (c) a user-assigned anomalies module that assists the user in identifying anomalies not related to corrosion; (d) entropy evaluation of hyperbolic regions; and finally, (e) clustering to generate condition maps. It is recommended that adopting such a holistic system leads to effective GPR data analysis, as the results would be closer to the ground truth and can be easily adapted by transportation authorities.

Recently, an investigation was carried out on the residual strength of a full-scale bridge that experienced 3 million cycles of rolling load. The test outcomes for two bridge deck sections measuring 3.81 m × 3.89 m × 0.21 m each are presented in this paper. The two sections are reinforced with glass fiber-reinforced polymer (GFRP) stay-in-place (SIP) form and GFRP rebar, respectively. Both reinforcement configurations were designed in compliance with the empirical design method specified in the Canadian Highway and Bridge Design Code (CHBDC). Prior to the punching shear test, both sections went through 3 million cycles of rolling load at a load level of 180 kN. The rolling load fatigue experiment was carried out using the Rolling Load Simulator (ROLLS) at Queen’s University, which is the first and only of its kind in Canada. This study aims to investigate the residual strength and failure patterns of bridge deck sections reinforced with GFRP SIP forms and GFRP rebar after extensive fatigue damage induced by realistic rolling loads.