Proceedings of the Canadian Society for Civil Engineering Annual Conference 2024, Volume 10

In recent times, the use of Glass Fibre-Reinforced Polymer (GFRP) as an internal reinforcement has gained popularity as an alternative to conventional steel bars in construction projects. GFRP offers advantages such as being lightweight, rust-resistant, having high tensile strength, and performing well mechanically. An important benefit of employing GFRP bars for reinforcement is their ability to prolong the lifespan of concrete structures with reduced maintenance needs. The combination of lightweight concrete and FRP reinforcement results in a building component that possesses significant strength relative to its weight. This characteristic allows it to support heavy loads while maintaining a lightweight profile, which is advantageous for reducing overall building weight. In this study, we aim to determine the flexural and Shear strength of a lightweight concrete beam using the Canadian codes CSA and ACI FRP guidelines. Subsequently, a practical test will be conducted to evaluate its load-bearing capacity in real-world conditions. The obtained results will then be compared and subjected to in-depth analysis. This research centres around comparing the flexural strength of an FRP-reinforced lightweight concrete beam with the outcomes of the conducted test.

Expansive agents have been developed decades ago with further development and incorporation within various Portland cement concrete applications. In this study, calcium sulfo-aluminate (CSA) and aluminum powder were evaluated as expansive concrete agents. The experimental program involved testing of fresh and hardened concrete properties including slump, compressive, and splitting tensile strength. Furthermore, the potential of the expansive agents in repairing beams was assessed experimentally together with the degree of expansion achieved by each of the two studied agents. Finally, non-destructive tests were conducted in order to assess the degree of porosity of the mixtures containing expansive agents. The results reveal that the two expansive agents yield promising results in terms of effectively causing significant expansion as well as repairing concrete beams such as bridge girders which can indeed be useful in many transportation structures’ works.

The incorporation of fiber-reinforced polymer (FRP) bars as internal reinforcement has become an optimal alternative to conventional reinforcing steel bars due to their innate corrosion resistance and high tensile strength. Storing substances like Liquefied Natural Gas (LNG), Liquid Nitrogen (LN2), and Liquid Oxygen (LOX) at temperatures as low as - 170 °C (− 274 °F) demand specialized equipment and materials. Understanding the behavior of glass fiber-reinforced polymer (GFRP) reinforcing bars in extreme cold is crucial. This paper demonstrates the behavior of FRP bars in extreme cold to investigate the thermal stability, ultimate elongation, and modulus of GFRP bars. It evaluates the mechanical properties of twelve sand-coated GFRP bars (#3; Ab = 71 mm2 and #4; Ab = 129 mm2) tested at - 170 °C (− 274 °F) and room temperature 25 °C (77 °F) as reference specimens. Microstructural analysis using scanning electronic microscopy (SEM) and physical measurements via thermogravimetric analysis (TGA) assess the deterioration of the fiber, matrix, and the fiber/matrix interface due to extreme cold. The test results indicate that the transition from room temperature to an extremely cold temperature may affect the FRP bars in two manners. Firstly, it increases the modulus and rigidity of the material, primarily the resin, enhancing mechanical properties. Secondly, dimensional changes occur due to the shrinkage of the two phases.

Corroded RC beam experiences different deterioration problems that affect its load-carrying capacity, namely loss of bond between reinforcement bars and the surrounding concrete, cracking or spalling of concrete cover, and loss in diameter of the rebar. This paper describes a study on three-dimensional (3D) finite element (FE) modeling carried out on the ABAQUS platform for the prediction of the static flexure load-carrying capacity of non-corroded and corroded reinforced concrete (RC) simply supported beams. The effectiveness of this three-dimensional (3D) finite element (FE) model was assessed by validating the simulation results with experimental test results available in the literature. In the present study, corrosion caused damages like bond loss, loss in the concrete cover region, loss in reinforcement area, and loss in reinforcement strength considered in the modeling of corroded beams. The cohesive surface interaction approach was used to simulate the critical bond behavior between rebars and concrete for both non-corroded and corroded RC beams. The modeling procedure in ABAQUS is cumbersome and requires significant attention if done using software GUI. In this study, to make the RC beam modeling procedure convenient and faster, a Python programming script was developed. The results show that the degradation in corroded rebars had a more significant effect on the load-carrying capacity of the member as compared to that of degradation of the concrete due to cracking and the degradation of bond-slip performance between the rebar and concrete. Degradation of the concrete cover region did not have a significant effect on the flexure load-carrying capacity while it had a significant impact on the corresponding deflection of the beam. The FE modeling results (including crack pattern, flexural strength, and stiffness) were found to be in close agreement with the corresponding experimental test results. The developed Python algorithm (script) alleviates significant modeling time with minimum inputs compared to that of ABAQUS GUI.

Knowledge of the behavior of precast concrete box culverts (PCBC) reinforced with glass fiber-reinforced polymer (GFRP) bars is still in its early stages and has been studied in a few articles. The current study examined the behavior of PCBC with GFRP reinforcement under shear. Two full-scale PCBC specimens were constructed and tested under CL-625 truck wheel load at critical shear location, as stipulated by the Canadian Highway Bridge Design Code (CHBDC) (CAN/CSA S6-19 in Canadian highway bridge design code. Canadian Standards Association, Mississauga, Ontario, Canada [1]) One specimen was reinforced with GFRP-reinforcing bars, while the other was reinforced with steel-reinforcing bars, both with the same reinforcement ratio of 0.83%. Both specimens had a span and rise of 1500 mm, and a joint length of 1219 mm. The slabs and walls were 150 mm thick, and the dimensions of the haunches were equal to the wall thickness. The findings show that using GFRP bars as internal reinforcement for PCBCs provides high load-carrying capacity that exceeds the ultimate design factored live load. This study suggests that GFRP bars can be a better alternative to steel reinforcement in PCBC applications.

Current lateral torsional buckling design provisions in the Canadian wood design standard CSA O86:19 stipulate that the lateral buckling capacity of built-up beams consisting of multiple plies is equivalent to that of a solid beam with the full width of the built-up system, provided that individual plies are securely connected at intervals that do not exceed four times the depth. Within this context, the present study numerically examined the lateral torsional buckling behaviour of built-up wooden beams consisting of two lumber plies of identical depth connected together through mechanical fasteners such as nails. The analysis was conducted using 3D finite element simulation that enabled the relative slip between plies. The study investigated the effect of fastener stiffness and spacing on the elastic lateral torsional buckling resistance and corresponding mode shapes for the built-up system. Comparisons were made against the buckling resistance of a single ply and that of a solid beam with a width of both plies. The study shows that the critical moment of the built-up system is found to be significantly lower than that implied by present design provisions based on a solid beam with full width.

The resistance of wooden beams with long unbraced segments is highly affected by their lateral torsional buckling (LTB) resistance. The LTB resistance in turn depends on support conditions, unbraced length, member cross-section, and loading conditions. While present design standards and past studies provide guidance on the effect of load height on the LTB for beams with a single unbraced segment, they offer no guidance for continuous beams with multiple unbraced segments. Within this context, the present study investigated the influence of load height on the LTB of continuous beams subjected to uniformly distributed and mid-span point loading. The investigation was conducted using finite element and energy-based solutions. The results show that applying present load height effect solutions intended for single unbraced segments to continuously supported beams can lead to unconservative LTB resistance predictions in the cases where loading is applied at the top face of the beam.

With the projected increase in the average and maximum temperatures in Canada owing to global warming, the deterioration rates of bridge infrastructure are expected to increase. Among the various deterioration issues in bridges, malfunctioning of the expansion joints is one of the most common. Although the cost of bridge expansion joints accounts for less than 1% of the total bridge construction costs, their maintenance costs can be as high as 8% of the overall bridge. Owing to the accumulation of debris and dirt in the joints, the axial movement of the bridge superstructure may be restrained, leading to axial forces at levels for which the structural members of the bridges were not originally designed. Consequently, it was anticipated that the presence of an axial force would reduce the moment capacity of the composite sections. In this paper, a literature review on the quantification of the moment resistance of concrete slab on steel girder (CSSG) systems subjected to the interactions of axial force and shear is provided. It was observed that moment–axial force–shear interaction relationships exist for sections with relatively shallow beams/girders. To test the applicability of positive moment-axial compression relationships to CSSG Bridges’ relatively deeper girders, a Finite Element Analysis (FEA)-based case study was conducted. The case study included a commonly used composite section in Canada with a 1200 mm deep web girder and a 225 mm thick concrete slab. The FEA model of the CSSG section was first subjected to pure positive bending to determine its composite moment capacity numerically. Subsequently, the change in positive moment capacity at different axial load levels was numerically investigated. The outcomes were compared with Canadian Highway Bridge Design Code (CHBDC) resistance models, as well as the positive moment-axial compression relationships found in the literature.

A few studies have examined the behavior of fibrous concrete columns reinforced with fiber-reinforced polymer (FRP) bars under eccentric loads. To examine the effects of various eccentrics and the addition of synthetic fibers to concrete on the eccentric compressive load behavior of the columns, three fibrous concrete columns reinforced with FRP bars were cast and tested under eccentric load in this study. The results showed that the specimens’ ultimate capacity under low eccentric loads was determined by the compression failure caused on by the crushing of the concrete. In addition, the flexural tension failure began in specimens evaluated under high eccentric loads. Finally, adding fibers resulted in improving the eccentric behavior of fibrous concrete columns.

Climate change poses significant challenges to infrastructure performance. Designing structures without accounting for potential failure mechanisms can lead to high mitigation expenses and increased risks to safety, serviceability, and durability. As a result, it is crucial for engineers to ensure structural reliability under extreme weather conditions and evolving climatic scenarios. The severity of such environments emphasizes the need for more resilient construction materials. This study investigates the potential use of high strength, corrosion-resistant stainless steel strands—specifically HSSS Duplex 2205—for pre-stressing applications. This advanced steel alloy presents a promising alternative to traditional carbon steel strands due to its superior mechanical performance and resistance to corrosion, particularly in marine environments. Although the initial investment may be higher, the material’s longevity contributes to lower life-cycle costs over time. In this research, HSSS Duplex 2205 is assessed by performing experimental testing related to the material’s chemical composition, mechanical properties, and stress corrosion resistance. The results demonstrate the desirable properties of the HSSS strands which are highlighted to showcase the construction industry the urge of using this material in aggressive marine environments. The chemical composition testing reflects the high content elements that provides better corrosion resistance properties. Tensile testing performed showed that the minimum requirements of ASTM were met. The low fracture strain and high modulus of elasticity were examined in depth concluding a dual fracture mode being experienced by the material. Thus, using the experimental work results in this research, a modified Mattock power formula for stress–strain has been proposed for the ACI-PCI-AASHTO codes. The newly proposed modified formula would account for the different properties that the HSSS Duplex 2205 material has than that of the conventional carbon strands. Furtherly, the stress corrosion cracking test showed a 64% decrease in corrosion rate when using a HSSS Duplex 2205 than using carbon steel.

Potential continuation or acceleration of climate change could increase the risk of critical bridge components or systems’ failure. This study investigates the impact of extreme climate loads, such as temperatures, on the safety and serviceability of a continuous slab-on-girder bridge. A three-span continuous slab-on-girder bridge designed according to the Canadian Highway Bridge Design Code was simulated by a 3D nonlinear finite element model. The bridge is investigated for the effect of different levels of temperatures combined with other gravity loads. The initial results show that the load over capacity ratio increases and exceeds 1.0 when the damage affects negative moment zones (over the interior supports). This may lead to a change in bridge classifications (from class 1 or 2 to class 4) causing the bridge to collapse. Further research is required to investigate the safety of the bridge elements, connections, and integrity of the bridge system while satisfying CSA-S6-19 design and evaluation requirements.

In recent years, several bridge failures have been observed around the world. These bridge failures are partially due to the lack of financial resources that forces owners to keep bridges in service under undesired circumstances. Given the importance that fatigue and overloading have been playing on bridge failures, the objective of this paper is to present an approach to assess the probability of failure of continuous highway steel bridge superstructures under the combined effect of fatigue damage and overloading. This objective is achieved by performing Monte Carlo simulations on a representative sample of medium length I-girder bridge configurations based on statistical data collected in North America. Damage location, permanent loads, truck gross weight, and axle configurations were assumed to be random variables. The probability of overloading events was modeled as a Poisson’s process. Accordingly, the probability of overloading events was found close to 10% on bridges with high traffic volume after being in service for about 100 years.

Researchers have investigated using glass fibre-reinforced polymer (GFRP) bars as the primary reinforcement in deep beams to overcome corrosion problems inherently associated with steel reinforcement. This study investigates the suitability of the strut-and-tie (STM) adopted by ACI 318 Code for GFRP-reinforced deep beams. A database of forty-two deep beams longitudinally reinforced with GFRP, without web reinforcement, all with shear span-to-depth ratios of less than 2.5, was compiled. Experimental data were employed to assess the implemented changes to the STM recommended by the ACI 318 (2019) code in comparison to the former version of ACI 318 (2014). The results revealed that the ACI 318 (2019) was more satisfying in capturing the capacity of deep beams than the older version of the ACI 318 (2014), with an average experimental to predicted value of 1.65. Additionally, the STM provided by ACI 318 (2019) yielded a high coefficient of variation of 45%.

Fiber-reinforced polymer (FRP) composites have significantly advanced construction technology by imparting superior properties such as high strength, durability, and corrosion resistance. Their application in concrete structures, particularly circular columns, has been especially notable. The bond integrity between the FRP composite and the concrete substrate is crucial for ensuring good performance and longevity of these composite structures. Debonding, defined as the separation of FRP from the concrete substrate, poses a substantial risk to structural integrity if it occurs. The guided waves’ technique is a promising method for detecting such defects. Among guided wave techniques, nonlinear guided waves have demonstrated significant efficiency for detecting and locating defects. In this research, we utilized a 3D finite element (FE) simulation approach to accurately predict the interaction of guided waves with debonding. Additionally, we developed a technique for the detection and localization of debonding. Various damage case scenarios have been considered to ensure the applicability of the proposed method in diverse situations. The findings demonstrate a good efficacy in utilizing guided waves to detect and locate minor bond defects within the cylindrical FRP-retrofitted specimens. The research also used advanced signal processing and analysis techniques to isolation the guided wave components for precise damage detection and damage localization.

On February 6, 2023, two major events shocked central Turkey, resulting in a great loss of life and massive destruction to the built environment in that area. Thousands of buildings were completely wrecked, whereas thousands were so badly damaged that need to be demolished. The main shortcomings and defects of failed structures are highlighted. The present research represents an attempt to assess the vulnerability of the building stock in Turkey. A performance-based seismic analysis of a typical multi-story R.C. building structure, that was designed according to TBEC-2018 (Disaster and Emergency Management Agency, Turkish building earthquake code: TBEC 2018 (pp. 1–416), Ankara, 2018), is performed. A plane frame model of an R.C. building, subjected to central Turkey's Main Shock of Mw7.8, is studied. The overall dynamic behavior of the RC building model is assessed. The following characteristics are examined: the model vibrating periods, story drift ratios, shear story, base shear, and local damage distribution along the height of the building. Enhancements to the original design of the building are performed to address the observed defects, during the actual earthquake. The overall damage indices, using modified Park-Ang damage index indication, for the enhanced models, are obtained and compared. The time history analyses for plane frame models are performed using computer code (Department of Civil, Structural and Environmental Engineering, University at Buffalo, IDARC2D. 2006: A Computer Program for Seismic Inelastic Structural Analysis, New York, 2006). The study output is based on analyzing and comparing the results of different models to infer some of the enhancements that should have been taken into account when designing and executing such buildings.

Dissimilar flexibility of the soil-foundation system among different legs of the lattice tower structures and possible differential settlement of each foundation could alter the structural tower’s overall behavior, failure mode, and final load-carrying capacity. Besides, lattice tower structures can experience bolt slippage and member buckling, and are subjected to material nonlinearity. This study aims to investigate the effects of differences in soil-foundation stiffness of lattice tower structures while other specific behaviors of such structures, including material nonlinearity, bolt slippage, the eccentricity of connections, and bolted joints stiffness properties, have come into account. To do so, performing incremental nonlinear analysis, advanced numerical finite element models of a complete lattice tower structure are developed, and different probable scenarios for foundation flexibility are defined. Foundation stiffness configurations that produce the worst effect on the tower strength are identified. The proposed model could be further developed to study the allowable limits of differential settlement for lattice tower design.

In Canada, approximately 90% of freight shipments are hauled by trucks. With the emergence of ‘Connected and Autonomous Vehicles’ (CAV) technology, trucks can form platoons to travel in close, high-speed formations. There is a gain in fuel efficiency but also increased load effects on existing highway bridges. The unique load patterns associated with CAV-enabled platoons necessitate a thorough review and upgrade of existing highway bridges to ensure their safety and serviceability. This study introduces a strategic approach to determine the priority of bridges for rehabilitation to ensure safe adoption of truck platooning. In particular, the approach utilizes a risk-based, multiscale assessment framework that integrates both component-level and network-level analysis to identify bridges that require urgent attention in preparation for truck platooning. At the component level, bridges are assessed for their load and current condition ratings, which inform their abilities to withstand the new loads introduced by platooning trucks. At the network level, the criticality of each bridge is evaluated using network topology measures to understand the potential impact of a bridge failure on the broader transportation system. Our assessment helps prioritize bridges that not only have structural deficiencies but also play a critical role in the transportation network. As a case study, the proposed approach is applied to determine highway bridges in Ontario with regard to their readiness for truck platooning. None of the examined bridges are grouped into the top two priority levels, indicating that critical bridges in Ontario are generally structurally adequate for the implementation of truck platoons.

Disaster mitigation and building code improvements are a major focus of modern wind engineering. While wind tunnel experimental work is a critical tool for the evaluation and development of building standards and codes, time and cost constraints limit its use in industry practice, particularly in low-rise design. One key example of this is the lack of evidence-based knowledge on the impact of building shape on the Main Wind-Force Resisting System (MWFRS). This is particularly overlooked for low-rise buildings, which are typically defined as those with a height-to-width (smallest horizontal dimension) ratio smaller than 1. Despite the prevalence of non-rectangular structures found in practice, guidelines for considering the MWFRS loads on low-rise irregular building shapes are not commonly found in design standards or building codes. Mathematical methods do exist to evaluate wind loading on non-rectangular structures; however, these are often too complex and time-consuming to be properly implemented in industry practice. The objective of this research is to present a comparison between boundary layer wind tunnel testing and the existing mathematical methods for determining wind pressures on irregularly shaped buildings, such as Cook’s Method and the inscribed method. The primary focus is on a range of T- and L-shaped building configurations with both vertical and horizontal irregularities. Six different modular rectangular shapes with different depth, height, and width ratios are combined to form a total of twenty-six models, which are analyzed using each method. This analysis identifies incompatibilities between predicted and actual MWFRS loads with the aim of applying this information to propose a simplified method for determining wind pressures on irregular shapes.

The impact of climate change on infrastructure, particularly dams, is significant. Studies have shown that Canada is likely to experience more rainfall and severe flooding events in the future, which could increase hydrostatic and sediment loads on existing dams. Moreover, climate change may lead to a more rapid deterioration of concrete dams. For instance, elevated temperatures can cause thermal cracking in concrete due to increased temperature differentials and may also increase the rate of Alkali-Aggregate Reactions. The expected increase in loads and deterioration rates could endanger the structural integrity of aging concrete dams and lead to failures. To date, dams have only been designed for stationary climatic conditions, and the effects of climate change have never been integrated into their design stage. Most dams in Canada were built before the 1960s; therefore, these aging structures do not meet the up-to-date design requirements. Consequently, the safety of existing concrete gravity dams is an ongoing concern for dam owners, as the aging processes can significantly alter their strength and stiffness. Furthermore, the revised projections of the maximum loads associated with severe floods triggered by climate change only add to the urgency of this matter. Therefore, it is necessary to conduct periodic reassessments of the structural stability of aging dams to ensure that they can withstand extreme loads beyond their original design parameters. In this preliminary study, a commercially available computer program was utilized to evaluate the stability of an existing large concrete gravity dam for various water levels. It was found that this computational tool could assist in conducting extensive parametric analyses for aging concrete dams under different extreme events and can be beneficial in evaluating the stability of dams in the face of climate change.

Concrete Slab on Steel Girder (CSSG) bridges are one of the most common bridge types in Canada. Web distortion is a plausible failure mode for girders of CSSG bridges with relatively deep webs, depending on the bracing conditions. It is a common practice to utilize shell element-based finite element models to capture complex buckling modes such as web distortional buckling. However, shell element analysis is computationally costly for modelling and interpreting their results requires expert skills. Compared with shell elements, beam element formulations capable of capturing distortional web behaviour may be a more feasible solution. However, commercial software often does not offer special beam elements capable of modelling the distortional buckling behaviour of thin-walled bridge girder components. The distortional beam formulations available in the literature are often used only via in-house coding; therefore, bridge owners, designers and researchers are generally not familiar or do not have access to modelling options with such specialized beam elements. To offer a more practical means of evaluating the web distortional buckling behaviour of steel girders, a set of beam-type elements has been formulated, namely DBF13. Some of the capabilities of one of these elements were previously demonstrated by comparing against shell elements in the literature. This study further expands the comparative evaluation of these beam elements to a variety of commonly utilized bridge girder geometries and restraint conditions through a parametric study. Firstly, a comparative analysis was conducted for a lateral torsional buckling case using several shell elements, both from ANSYS and ABAQUS elements libraries as well as DBF13 beam elements. Then, the predicted buckling loads and shapes for web distortion-type buckles were presented for the developed beam elements and ANSYS SHELL281 element. The current limitations and future development plans are outlined.

Many structures in civil engineering are excited by dynamic forces, which may be generated by earthquakes and winds. While deterministic models have traditionally been used to describe these forces, stochastic models offer a more realistic representation, including white noise processes, real noise processes, or bounded noise processes. The moment Lyapunov exponent, a key tool for analyzing the stochastic stability of structures, has primarily been applied to linear systems. However, its applicability to non-linear structures remains underexplored. In this paper, the stochastic stability of strongly non-linear structural systems subject to parametric excitations of white noise processes is investigated through moment Lyapunov exponents. The method of stochastic averaging is formulated to derive a system of stochastic differential equations. Then Khasminskii’s transformation is applied to determine the moment Lyapunov exponent. The proposed procedure is applied to study the stochastic stability of the plane motion of a beam under axial stochastic compressive load. The stability conditions are determined by examining the behaviors of the averaged square-root of total energy at its boundaries. Understanding structures’ stability and their response to dynamic loads will lead to efficient structural design.

Structural Health Monitoring (SHM) has become a crucial activity in civil engineering to enhance the performance of aging infrastructure. With the unprecedented evolution from Industry 3.0 and the world of next-generation sensing technologies, the beginning of the fourth industrial revolution (Industry 4.0) has brought forth recent advancements such as Internet-of-Things (IoT), Big Data analytics, cloud computing, and cybersecurity to automate and leverage SHM methods over traditional inspections. However, connecting these technologies and establishing a comprehensive and autonomous digital framework for SHM applications have been a challenge. Presenting real-time processed SHM data in a live digital interface faces various hurdles, including data transfer delays and the need for manual processing using offline tools. This study, hence, explores emerging building information modeling (BIM) and IoT via an Arduino microprocessing unit to track and visualize data from time and frequency domains in real time. It aims to enable continuous data monitoring, real-time data processing, and storing data in a web-based database rather than relying on offline resources that require manual intervention. The data subsequently moves from the IoT device into a structured online database into BIM with the help of the latter’s visual scripting interface. The proposed real-time SHM method is experimentally validated using a laboratory application: a randomly excited three-story model under different health conditions. Generative warning dispatches are visualized via automated threshold monitoring of both time and frequency domains under normal healthy conditions. The research thus exhibits static and dynamic data in a comprehensive BIM database while ensuring an automated and live workflow that empowers decision-making.

The City of Los Angeles (LA) transportation network includes more than 1300 state and local bridges, which are vulnerable to the earthquake shaking. Seismic damage to these bridges will incur significant repair costs and hinder post-earthquake emergency response and long-term recovery of LA communities. This study conducts a stochastic event-based regional seismic damage assessment of LA's bridge network. The bridges that comprise the network vary based on the construction era, geometry, connectivity, material properties, and design detailing. To capture these variations, Google Street View and the US National Bridge Inventory (NBI) database are used to classify the LA bridges into 26 groups based on their abutment type, construction era and the number of spans and columns. Subsequently, a new generation of component-level seismic fragility models is synthesized from the literature and assigned to each bridge group. The fragilities capture damage to columns, bearings, shear keys, joint seals, deck (unseating), and foundation. The new-generation seismic fragilities, which represent a significant advancement relative to existing models for California bridges, were developed using finite element models that explicitly capture component-level demands and limit states across the identified 26 bridge groups. The third Uniform California Earthquake Rupture Forecast (UCERF3) model is used to generate 1000 earthquake catalogs in 50 years. Each catalog produces approximately 400 earthquake events throughout California. Region-consistent ground motion prediction equations and spatial correlation models are applied to simulate 100 ground motion random fields (GMRF) under each event. The GMRFs are then convolved with the fragility models to estimate the distribution of shaking intensities at each bridge location and the associated component-level damage state exceedance probabilities. Damage assessment results from the current study facilitate the development of seismic risk and resilience models of the LA bridge network. The ultimate goal is to inform risk- and resilience-based seismic retrofit programs, as well as post-earthquake decision-making and restoration planning for the City of LA.

A timber-concrete composite (TCC) system consists of a timber member and a reinforced concrete slab with a shear connection at their interface. TCC systems offer many advantages compared to single-material schemes, including lighter floors, lower embodied carbon, and longer spans. A key design criterion for TCC floor systems is the deflection limit imposed by building codes. Long-term deformations in TCC systems are mainly due to the sustained long-term load (due to the viscoelasticity of concrete and timber) and changes in environmental conditions. Slip in the connection between timber and concrete can also increase under sustained loads over time. Therefore, when determining the final deflection of TCC systems, the long-term behaviour of the component materials and the connection should be considered. While there is a substantial knowledge base on the long-term behaviours of timber and concrete individually, knowledge of long-term deflection in TCC systems is limited. This study addresses this gap by investigating the long-term performance of selected TCC connections through a creep test programme. The tests will generate displacement versus time responses of TCC connections, leading to developing related creep coefficients that could be implemented in design standards. Further validation of the experimental results is planned via numerical modelling.

This paper presents an investigation into the analytical modelling of the behaviour of unreinforced and fibre-polymer reinforced short-span glulam beams. The research programme evaluated a total of five unreinforced and nine reinforced glulam beams that were tested to failure under four-point bending. The reinforced configurations consisted of two or four layers of simple tension and U-shaped tension FRP reinforcement. A comparison between the experimental and predicted load–displacement curves is presented, highlighting the discrepancies in the experimental and predicted displacement at the maximum load. The impact of the modification factor, αm, in the model was also investigated. The analysis did not use a modification factor as no wood tensile strain enhancement observed due to alternative failures modes such as horizontal shear and simple tension failure at the FRP termination points occurring instead of a flexural failure in the maximum moment region. The effects of FRP development length, the corresponding stress concentrations at the start and end of the FRP reinforcement, and inherent shear strength of the glulam relative to the modification factor, αm, should be considered for future models to accurately predict the appropriate failure mode.

The results of an experimental testing programme on 12 weld-critical axially loaded circular hollow section (CHS) X-connections with large branch-to-chord diameter, β-, ratios (i.e. 0.50 < β ≤ 1.00) are presented. Measured load–displacement response, weld fracture load, and strain distributions are used to evaluate the weld-effective length phenomena. A reliability analysis is conducted to assess the level of safety obtained when extending the weld-effective length formulae provided by CSA W59:23 for CHS X-connections with small β-ratios (i.e. 0.10 ≤ β ≤ 0.50) designed as “fit-for-purpose,” and recommendations are made for the further development of Section 4.8 of the standard.

The objective of the experimental program was to conduct tests on concrete beams reinforced with glass fiber-reinforced polymer (GFRP) bars, which were exposed to severe simulated marine conditions and subjected to flexural loads. Three GFRP-RC beams, all with identical dimensions (cross-section of 300 × 200 mm and a length of 3000 mm), were utilized for this study. This included an unconditioned reference specimen, along with two conditioned beams that had undergone an accelerated aging process designed to replicate the behavior of concrete components exposed to seawater. To achieve this, all the bars and stirrups in the two conditioned beams were submerged in a tank containing a 3.5% salt solution and placed in a high-temperature chamber at 60 °C for periods of 3 and 6 months, respectively. The experimental results were presented in terms of the flexural behavior of the tested specimens, load-bearing capacity, propagation of cracking patterns, and modes of failure. The results of this study demonstrate the feasibility and effectiveness of using GFRP bars to reinforce structural elements in environments susceptible to external aggression.

Maintaining and monitoring underwater infrastructure, key to efficient and low-risk asset management, relies heavily on underwater object detection (UOD). Sonar, favored in murky, low-light underwater conditions, faces challenges like low resolution and poor contrast in its images, affecting object detection accuracy. This paper introduces a novel deep learning approach for UOD using multibeam forward-looking sonar data, leveraging the YOLOv7 (abbreviation of You Only Look Once version 7) architecture. It includes tailored improvements in data preprocessing, feature fusion, and loss functions, outperforming existing sonar methods in object classification. Tested on an underwater remotely operated vehicle (ROV), the proposed framework shows enhanced target classification and transfer learning, suggesting potential for broad application in underwater structural monitoring and autonomous management.

The use of encased steel profiles in concrete columns is a well-established technique in the field of building construction. However, the utilization of this technology in bridge engineering, especially in areas prone to seismic risk, has not been thoroughly investigated. Since the steel profile inside the concrete has more cover than the outer bars, it will be preserved in a harsh environment, which leads to an increase in the durability of the system. In addition, utilizing the core steel element in retrofitting processes provides the required resistance, allowing for structural work to be conducted without the need for rerouting traffic, which ensures the continuous flow of traffic and enhances public comfort. As a first step in the research, the potential use of the proposed system in low and moderate seismic regions like Montréal is studied. The effective stiffness of the steel–concrete composite circular columns and its subsequent effect on the seismic demand imposed on them are investigated and compared to that of reinforced concrete (RC) columns. Also, using a real-dimension model of a bridge made with CSI-Bridge software, a comparison is made between the performance of RC piers and the equivalent alternative composite system in terms of structural response, columns factored, nominal, and expected resistance in low and moderate seismic zones. The Canadian code CSA S6-19 requirement design criteria are used to design both RC and composite columns by the force base design (FBD) method. The results show that the composite system can act similarly to RC piers concerning the parameters under consideration.

The Egyptian Social Housing Program (ESHP) is a national project launched in 2014, that aims to construct one million residential units around the country. Within the framework of the ESHP, more than 26,700 Reinforced Concrete (RC) buildings have been constructed; each has 24 residential units. An additional 15,000 buildings will be constructed by 2030. It was noted that an almost identical design for the RC superstructure was adopted for all constructed buildings regardless of their seismic zone. To ensure the safety and resilience of this ESHP typical design to withstand future earthquakes, a performance-based evaluation was conducted for the ESHP typical RC building using SeismoBuild software. Nonlinear pushover analysis of the ESHP typical RC building was performed. The capacity and demand curves were compared to assess the seismic resistance of the ESHP building in the various seismic zones located in Egypt. The global performance of the ESHP building was investigated in terms of the lateral capacity curves with performance points in different seismic zones. Additionally, the inter-story drift ratios were assessed to identify the damage quantities along the building stories. Furthermore, the local performance of the primary structural elements was evaluated in terms of the generation of the plastic hinges and the shear failure. The results showed that the ESHP buildings have adequate performance in all the seismic zones of Egypt with recommendations for design enhancements in only the highest two seismic zones.

In geotechnical engineering, slope stability analysis has been of long-lasting interest to ensure the safety of embankments. A wide range of theoretical, numerical, and experimental techniques has been applied extensively to calculate the factor of safety, while the use of intelligence-based approaches has promised a new paradigm shift with an ever-increasing application. However, the black-box nature of artificial intelligence (AI)-driven tools, in which the internal mechanism in making decisions by the AI-centered decision support systems is not clear even for developers, has a damper effect on its usage where the consequences can affect human safety. This paper addresses the problem of lack of reliability and transparency in the machine learning (ML)-assisted safety factor prediction of embankments. A dataset of different slopes is tainted via a group of ML techniques automatically. Then, the best-tuned one is utilized for explainable AI (XAI)-powered exploration of input parameters. In particular, Shapley Additive exPlanation (SHAP) analysis allowed for understating about the most important contributing factors and their interactions in an interpretable way. This study prepares the ground for applying intelligent safety factor prediction tools in a reliable and transparent style.

Globally, the construction industry contributes to 33% of carbon emissions and 40% of energy consumption; therefore, it is essential to find greener construction alternatives to reduce such emissions. Structural Insulated Panels (SIPs) proved to be a sustainable option in building construction due to their excellent thermal performance, leading to a major reduction in energy consumption. Subsequently, this study aims to develop sustainable (SIPs) using Wood Plastic Composites (WPC) and insulating foam, focusing on mechanical strength and thermal efficiency while leveraging recycled and waste materials. The SIPs investigated are an assembly of Wood Plastic Composites and insulating foam. Mechanical tests were conducted on the WPC including flexural strength, compressive strength, tensile strength, bending modulus, and water absorption. The results showed 37 MPa flexural strength, 28 MPa compressive strength, 12 MPa tensile strength parallel to extrusion, 7 MPa tensile strength perpendicular to extrusion, bending modulus of 4766 MPa, and water absorption of 1.30%. For the insulating materials, Extruded Polystyrene (XPS) was investigated in different densities to determine its thermal conductivity. For the SIPs assembly, two adhesives were utilized, which are Polyvinyl Acetate and Sodium Silicate. Both adhesives did not influence the compressive strength of the composite. Moreover, mechanical tests were conducted on the entire SIP including compressive strength, core shear strength, and the thermal conductivity of the SIP was compared to a traditional masonry cement wall. Furthermore, carbon emissions associated with SIP production were compared to conventional reinforced concrete (RC) to quantify the relative sustainability of the proposed panels.

Buildings are getting taller, slenderer, and more susceptible to wind-induced motion. Increasing mass or stiffness are options considered to control building responses, requiring more construction material and less useable floor areas. Alternatively, performance-based damping systems may be considered. Performance-based damping marries the fields of structural dynamics and damper technologies together with wind engineering and wind tunnel technologies to develop optimum damper designs proven to improve building performance. The paper presents case studies of two main types of damping technologies that have been successfully implemented in projects worldwide: tuned mass damper (TMD) and tuned sloshing damper (TSD) systems. One component of performance-based damping that was key to their successful implementation is the constant coordination with the client. The use of irregular-shaped TSD systems to fit within project spatial constraints highlights another important aspect of performance-based damping: having rational or scientific basis via laboratory-scale testing. Another case study, where the damper mass was determined based on first-principles-based tools, was later reduced in size after nonlinear time domain analyses were used. Finally, case studies that involve innovative TMD systems with more complicated pendulum configurations and requiring less space than simple pendulum TMDs, are discussed. In each of these case studies, a monitoring system was installed that simultaneously recorded damper and building motions, with the data processed to demonstrate how the modelled performance of the damping system is in close agreement with the as-built performance.