Proceedings of the 2nd International Conference on Advances in Civil Infrastructure and Construction Materials (CICM 2023), Volume 1

An innovative steel braced frame system is introduced that is designed and detailed to exhibit an elastic self-centring hysteretic response and achieve damage-free seismic response for low-rise building structures. The system is implemented in the first storey of buildings so that all seismic-induced deformations intentionally develop in that storey to obtain a seismic response similar to that offered by base isolation systems. The proposed system is first described together with a design approach that is based on the single-mode analysis method widely adopted for the design of base isolation systems. The system is applied for two- to three-storey office buildings located in the high seismicity region of Vancouver, British Columbia, Canada, where the seismic hazard is contributed by shallow crustal, deep in-slab, and interface subduction earthquakes. Nonlinear response history analysis is performed under site representative ground motion records to verify the seismic performance of the proposed system. The study shows that the system can exhibit enhanced seismic performance in terms of peak lateral displacements and peak horizontal floor and roof accelerations, with no structural damage nor residual deformations. The results also suggest that peak lateral displacements can be reliably predicted using the simple single-mode method for base isolation systems.

Natural hazards that have been occurring in various forms, frequencies, and intensities are unavoidable. However, developing a resilient built environment for these natural hazards is achievable. Among multiple ways of achieving community resilience, the Structural Extreme Events Reconnaissance (StEER) Network focuses on “Building Resilience through Reconnaissance.” This approach uses data and observations after natural hazards to make a difference directly on the affected communities, to guide related research, and to inform policy, rather than the regular sequential cycle of these aspects. For data collection, a worldwide trend is the expansion of sensor installation on different elements of the built environment. The acquired big vibration and vision datasets from continuous monitoring and reconnaissance efforts are used to study the response of structures (e.g., buildings and bridges) and ultimately improve design code provisions and practices. The effective and accurate collection and use of data rely on advances in Structural Health Monitoring (SHM) to improve the sustainability and resilience of cities and communities. This paper focuses on the activities of the StEER Network and two frameworks that use different modalities of data for achieving resilience using SHM and reconnaissance: (1) The establishment of the “Bridge Rapid Assessment Center for Extreme Events (BRACE2)” for real-time and near real-time vibration-based SHM and operational decision-making of instrumented bridges and (2) The development of a hierarchical database, namely, “PEER Hub ImagNet” ( $$\phi$$ ϕ -Net) for integrating multi-task deep learning mechanisms for vision-based SHM using images.

This study explores a single-component geopolymer concrete (GPC) formulated with a blend of low-calcium fly ash and ground-granulated blast furnace slag (GGBS). The objective is to develop a Portland cement-free GPC with minimal energy-intensive alkali activators, resulting in a general-use composite with a compressive strength exceeding 10 MPa. Additionally, the study explores the effects of specific grade graphene nanoplatelets (GnP) on GPC at the nanoscale. The research includes testing of fresh properties, compressive strength, water absorption, and chloride resistance. An optimized GPC mixture achieved compressive strengths of 16.16 MPa at 8 days and 18.31 MPa at 34 days. GnP demonstrated promising enhancements to GPC, including a 54% increase in strength and a 13% reduction in water absorption capacity. GnP exhibits notable resilience to efflorescence, with a positive influence on the mechanical properties of GPC.

RC structures, in general, are susceptible to chloride-induced corrosion in saline/marine exposure due to their inherent permeability characteristics. The corrosion initiates within a RC element once the chloride concentration at the surface of embedded reinforcement reaches to a critical value. Such initiation of corrosion is usually minimized following two techniques: (i) by reducing rate of diffusion of chloride ions through concrete matrix and (ii) by providing adequate cover so that chloride ions would require longer travel distance to reach the surface of embedded rebars. Chloride diffusivity is usually reduced by selecting proper binder types that would guarantee long term pore refinement through pozzolanic reactivity. In case of cover requirement, it should be designed considering both construction feasibility and economy. Hence, in order to ensure design service life of a RC structure in saline conditions, a concrete mix needs to be properly proportioned with appropriate binder types that would keep the required cover values within feasible limit. A performance-based design approach can ensure such suitable combination of concrete mix proportions and cover requirements. However, no performance-based guidelines for marine concrete are available in Bangladesh focusing specific demand of the country. Considering the significance of the subject matter, an attempt has been made in this article to discuss the importance of performance-based design and techniques to achieve it based on outcomes of the previous studies.

A test database of the compressive strength of masonry units and masonry prisms has been developed through a detailed literature review. The test results are compared with the compressive strength of similar masonry walls/prisms predicted by the design equations of the Australian masonry standard. It can be seen that the design equations of the Australian masonry standard often overpredict the compressive strength of masonry. A simple equation developed through a regression analysis of the test results is proposed, which can be useful in estimating the compressive strength of masonry from the compressive strength of the unit.

Asphaltene is one of the key chemical species of bitumen and generally dictates its stiffness-building behavior. The separation of asphaltene from bitumen and its gravimetric as well as chemometric analysis paves the way for a better understanding of bitumen behavior. Asphaltene is generally precipitated from a solution of asphalt in a non-polar solvent (such as n-heptane) where more-polar asphaltene precipitates from a solution. This study investigates the effectiveness of different solvent ratios of n-heptane/toluene solution, in separating asphaltene from bitumen due to changes in Hansen/Hildebrand solubility parameters. The experiment involved gradually varying ratios of n-heptane and toluene solvents such as 90:10, 80:20, and so on. A 50:50 solvent ratio was also examined to compare its effectiveness against using 100% of either solvent. Hansen solubility parameters were utilized to see the changes in different parameters due to the mixing of different solvents. The findings revealed that the solvent ratios influenced the asphaltene’s gravimetric yield percentage. Remarkably, the 50:50 solvent ratio demonstrated comparable results to those achieved using 100% of a single solvent of n-heptane. This outcome highlights the potential for cost optimization as well as redundancy by reducing the amount of solvent required while maintaining the asphaltene separation efficiency. The gradual changes of asphaltene yield also indicate that asphaltene is not a single chemical element, but a distribution of molecules of varying polarity. The abstract should summarize the contents of the paper in short terms and should contain up to 300 words.

Concrete is one of the most widely used construction materials, with cement being a key component. However, cement production is associated with a significant carbon footprint. To address this issue, there is a growing demand to partially replace cement with less carbon-intensive binders to create sustainable concrete structures. The chemical composition of these new binders changes the fire resilience requirement of sustainable concrete, which affects the design of concrete slabs. Consequently, changes in concrete volume and cement quantity are expected in the construction of sustainable concrete slabs. This study aimed to investigate how the changes in fire resilience requirements influenced the changes in concrete volume and cement requirements for slab construction. The study involved designing numerous concrete slabs with different spans, loads, and durability conditions as per standard, focusing on minimising the slab thickness. The slabs were then redesigned to meet various fire resilience requirements, and the changes in concrete volume and cement content were compared with the standard design. The study’s findings indicated that changes in fire resilience requirements significantly affected concrete slab design, leading to adjustments in concrete volume and cement quantity. Therefore, the study highlighted the importance of considering fire resilience in the design and construction of sustainable concrete structures with implications for the cement industry and construction sector, which are significant contributors to global carbon emissions.

Presently, reinforced concrete (RC) bridges are designed to survive significant natural and man-made hazards without collapsing; however, concrete damage and the rebar yielding are permitted. Excessive damage increases downtime, and sometimes the structure is beyond the repair stage and must be replaced. Shape memory alloy (SMA) rebars have been used extensively recently to enhance the behavior of structures in seismically active regions and limit their permanent damage, particularly when experiencing strong loads and seismic activity. Although the effectiveness of SMA as reinforcement in seismic-resistant design is well documented, performance of SMA-RC bridges under various multi-hazard scenario is not well understood. To investigate the resiliency of RC bridges against multi-hazard scenarios, this paper discusses the performance of SMA-RC bridges under three extreme loading scenarios such as earthquake, vehicle collisions, and extreme wave loads. This study will present the details of the vehicle collision and wave load simulation in finite element environment. The results will be compared with conventional steel-RC bridges under similar loading conditions. The findings of this investigation will facilitate comprehension of the advantages of SMA as longitudinal reinforcement for improving the multi-hazard resiliency of highway bridges.

Climate change significantly challenges civil infrastructure systems, which are crucial for societal needs and economic development. To address this, climate resilience-based design has emerged as a vital approach to mitigate climate impacts on infrastructure and enhance adaptability. This design approach considers climate change across the entire infrastructure life cycle, from planning to operation. Resilient designs can minimize vulnerability through climate projections and risk assessments by understanding potential climate hazards like temperature increases, sea-level rise, extreme weather events, and altered precipitation patterns. Key strategies for climate resilience-based design include bolstering infrastructure robustness and redundancy, decentralizing critical services, employing nature-based solutions, and adopting adaptive management approaches. These strategies aim to improve the infrastructure's capacity to endure and recover from climate disruptions while maintaining functionality and minimizing economic losses. Interdisciplinary collaboration, stakeholder engagement, and long-term planning are emphasized in climate resilience-based design. Integrating climate science, engineering expertise, socioeconomic considerations, and policy frameworks can lead to sustainable and adaptive infrastructure solutions. Flexible design standards and regulations accommodating changing climate conditions are also vital. Implementing climate resilience-based design requires a paradigm shift in traditional engineering practices. Proactively considering current and future climate scenarios and prioritizing adaptive measures is necessary for infrastructure longevity and effectiveness. Embracing climate resilience-based design enables infrastructure to withstand climate change challenges and contributes to overall community sustainability and well-being. In conclusion, climate resilience-based design offers a holistic framework to develop robust and adaptive civil infrastructural systems amid climate change. Integrating climate considerations, stakeholder engagement, and innovative strategies can enhance infrastructure resilience, reduce vulnerability, and meet society’s needs amidst a changing climate.

Externally bonded method of CFRP laminate has been widely used for shear strengthening of reinforced concrete beam. However, CFRP laminate could be debonded at concrete interface with lower strain as compared to its ultimate strain due to lower bond strength of concrete. The laminate could also debond with concrete cover separation after yielding of internal shear reinforcement because of strain incompatibility behaviour between elastic stiff nature of CFRP laminate and plastic deformation of steel shear reinforcement. Interfacial debonding could be eliminated through appropriate design of laminate with simple mechanical embedded connector anchor system; however, cover separation failure could not be eliminated through anchor systems rather than replacing of CFRP with elastic soft FRP material. In this regard, natural jute fibre-reinforced polymer (JFRP) laminate would have huge potentiality. This research aimed to present guidelines for shear strengthening of RC beam using CFRP and JFRP laminates with embedded connector anchor systems. The parameters of guidelines had been verified through analysis of experimental results of shear-strengthened RC beams. Results showed that the cross-sectional area of CFRP and JFRP laminates obtained from the design guidelines enhanced the maximum shear capacities of strengthened beams. Both CFRP and JFRP laminates strengthened beams had almost similar shear failure loads. The beams had failed after yielding of shear and flexural reinforcements without debonding of laminates. The presented design guidelines of shear strengthening could be used in practice to retrofit RC structures.

The updated Bangladesh national building code (legally enacted as BNBC-2020) contains new seismic design provisions including a new seismic zoning map dividing the country into four seismic zones with seismic zone coefficients varying from 0.12 to 0.36. This paper briefly explains the salient features and significance of these provisions which were finalized way back in 2010. Since then there have been new developments and new research in the field of seismological research and earthquake engineering. A general appraisal is done on some of the important code provisions related to seismic loads through brief comparison with other building codes and research publications both new and old. Several seismic hazard assessment studies, both probabilistic and deterministic, have been conducted for Bangladesh adopting different procedures. Particular reference will also be made to a recent publication indicating the possibility of a mega earthquake (magnitude 8.2–9.0) deep inside Bangladesh. Bangladesh is located at a complex seismo-tectonic regime close to the plate boundaries of Indian plate and Eurasian plate in the north as well as plate boundaries of Indian plate and Burmese sub-plate in the east. It is emphasized that it is indeed a great challenge to conduct seismic hazard assessment of Bangladesh and several years of coordinated seismological research work needs to be carried out for a realistic assessment.

Concrete-filled steel tubular (CFT) columns are becoming more widely used because of their superior strength and ductility. Another benefit of CFT is that it eliminates the need for formwork during construction. The accurate behavior of concrete under compressive cyclic loading is particularly important for the seismic-resistant design of structures, as the tensile strength of concrete is often neglected in the design of steel–concrete composite structures. In the present study, a confinement model for cyclic compression has been proposed which can predict the behavior of concrete confined in a circular CFT column. The proposed model is inspired by the previous models of cyclic axial compression developed for concrete confined either with steel reinforcement ties or with fiber-reinforced polymer (FRP). The main components of the cyclic model, i.e., the envelope curve and the loading–unloading curves, are suitably modified to accurately represent the behavior of concrete in a CFT column. In addition to the concrete strength, steel tube strength, and tube diameter-to-thickness ratio, the proposed model also considers the effect of the length-to-depth ratio of the CFT column. Further, the proposed model has been validated with the experimental results and can reasonably predict the peak as well as post-peak behavior.

Prestressed concrete bridge girders (PCBG) are susceptible to damage when exposed to overheight vehicle collisions. This paper presents high-fidelity finite element models developed using LS-DYNA software. Thirteen models were validated against experimental data from the literature. The validated models were then implemented to perform a parametric study investigating the key factors affecting the dynamic response of PCBG under vehicle collisions, including vehicle speed and mass, girder span, and girder type. The response of each girder was quantified in terms of impact force time histories. The study revealed that relying solely on metrics such as peak impact force, kinetic energy, momentum, and impact speed is insufficient for accurate girder dynamic response representation. The collision time is a critical factor that needs to be incorporated. Thus, the most critical factor that can represent uniquely the dynamic response of prestressed girders is impact impulse. The results of this study can assist in the quantification of the dynamic demand and the development of design guidelines that will enhance the safety and resilience of prestressed bridge structures.

Experimental validation of nonlinear finite element analysis of reinforced concrete (RC) and prestressed concrete (PC) structures is presented, with emphasis on life-cycle assessment of bridges under corrosion. Structural modeling is developed with different levels of complexity using RC/PC beam finite elements and bi-dimensional finite elements for plane stress analysis. The proposed models are validated on the results of experimental laboratory tests on corroded RC beams and full-scale load tests on 50-year-old PC bridge deck beams. The comparison between numerical and experimental results allows to validate the proposed nonlinear analysis methods of corroded RC/PC structures.

The structural design of emergency shelters is important to ensure sustenance for the post-disaster period of the vulnerable Rohingya community. Bangladesh ranks fifth most disaster at-risk country and is more vulnerable due to giving shelter to 943,000 Rohingya inhabits until October 2022. This paper aims to propose a conceptual prototype for the emergency shelter considering both architectural and structural aspects. The structure will be resilient with a permanent and stable core to withstand cyclone hazards, while the dwellers can easily construct additional bamboo structures in the post-disaster period for temporary living. Locally available bamboo and structurally stable steel beams supplied by the government or non-profit organizations will be used as primary building materials. The methodology includes mixed methods of site selection and analysis, structure considerations, and conceptual design proposal. The findings will show the structural strength of the proposed prototype due to the effect of a cyclone. The scope of this paper is a further stable shelter based on the given prototype that the users can use for a more permanent structure with a higher lifecycle and resilience. The lack of a physical survey and real-scale structural analysis of the proposed design are identified as the paper's limitations. In conclusion, it can be said that the post-disaster shelter issue of the vulnerable Rohingya community should be tackled with expertise. A simulation-based prototype with a stable core and low-cost sustainable bamboo will give assurance to the temporary shelter.

Concrete-filled steel tubular (CFST) member is a composite of infilled concrete core and outer steel tube. In recent decades, CFST members has paid high attention to the researchers due to many reasons. CFST technology uses the benefits of both concrete and steel to increase the strength capacity. The experimental study is quite limited due to scarcity of laboratory facility and test time consumption. Therefore, this paper deals with the validation of the experimental data using numerical software ABAQUS to figure out the mechanical and confinement behaviour of the CFST columns. A total of 15 CFST columns (stub and slender) have been taken with three different shapes which are categorized as circular, rectangular and square sections. The CFST columns were made with different concrete strength, slenderness ratio. The simulation results were verified with the experimental data. From the comparison, it is noticed that the numerical results can accurately capture the experimental results. It is also observed that the confinement on lower strength concretes was higher than the higher-grade concrete strength.

Structural steel members develop residual stresses due to manufacturing and fabrication processes. Depending on size and welding procedure, these residual stresses in steel members can vary significantly in magnitude and distribution. Hence, it is challenging to reliably predict the magnitude and distribution of residual stresses in steel structural members and connections which can substantially affect their structural performances including local and global flange buckling strengths, seismic performances, and low-cycle fatigue responses. Residual stresses are either ignored or a simplified distribution is assumed in the analysis and design of structural members. This paper presents a numerical scheme to simulate multiaxial residual stresses in steel structural members and connections by using a sequentially coupled thermo-mechanical analysis. Residual stresses induced by welding processes and nonuniform cooling after hot rolling are simulated. The analysis considers the effects of phase transformation, the material heterogeneity in the heat-affected zone induced by welding, and the weld sequence. The simulation technique is validated against several experimental responses demonstrating the robustness of the simulation scheme. The developed numerical scheme provides an advanced technique for simulating multiaxial residual stresses in structural steel members and connections for use in structural analysis and design of steel building frames.

To enhance the economic growth of a nation, efficient and affordable mobility of people and transportation of goods are essential. In this regard, highway bridges—one of the key components of highway transportation networks—play a pivotal role. Generally, bridges are designed to survive against design loading during the life span. However, unpredictable natural disasters such as extreme floods may endanger the safety and serviceability of bridges during their design life and produce a tremendous economic loss to the society they serve. This very important matter is currently being investigated by the structural engineering community, and more studies are required to develop a comprehensive knowledge base on the topic. In this relation, the study here considers a representative steel girder bridge and analyzes its response under possible flood scenarios. Several bridge design provisions for floods are reviewed, and representative cases of flood load on the bridge are formulated. Numerical simulations for different flood-induced loading cases with various combinations of flood velocity and water height reveal that the flood vulnerability of the bridge increases with velocity and water level. The debris loading increases by 1.5 times its hydraulic pressure when they act concurrently. However, after a certain level of flood height, the hydraulic pressure does not change, whereas the debris pressure continues to increase with increasing water height. The outcome of this research provides a better insight into the problem and identifies key areas for future research to improve the failure probability of bridges under extreme floods.

To withstand lateral stresses like wind and earthquakes, steel buildings require lateral load-resisting systems called steel plate shear walls (SPSW). The current study aims to analyze how different geometric and material characteristics affect unstiffened steel plate shear walls when subjected to cyclic loads. A three-dimensional full-scale finite element model for a single panel has been developed using finite element software to predict hysteresis behavior. The numerical model includes both geometric and material non-linearities. The FE modeling approach has been verified through previous experiments. The current analysis and previous experimental results have demonstrated a satisfactory agreement, proving the validity and admissibility of the present model for further parametric study. By using non-linear monotonic, the investigation has then focused on studying the effect of using different column sections on an unstiffened single-panel SPSW for varying thickness. The monotonic behavior, including the strength and load-resisting capacity of the SPSW with respect to the bare frame, has been examined. The bare frame contributes more to the strength gain of a large column section whereas the thickness of the infill plate contributes more to the strength gain of a smaller column section system. A detailed discussion of the result is presented, along with a comparative analysis of the behavior of SPSW having different column sections and geometric configurations.

This study focuses on the importance of flush end-plate connections in steel structures and the potential for failure if bolts are damaged, leading to shear, bending, or fatigue failure. To avoid failure, it is critical to predict the connection’s moment capacity against anticipated loads and design criteria. Simulated results from experiments and numerical simulations were compared with actual results. Current finite element models and experiments have shown limitations in making accurate predictions. This paper developed improved machine learning techniques to accurately forecast moment capacity, using various parameters such as bolt diameter, end-plate width, and nominal yield stress. To create our models, a wide range of works with data spanning 25 years were examined. The analysis illustrated that among all the ML models that were examined in this study, the eXtreme Gradient Boosting (XGBoost) model demonstrated the best prediction performance which is also confirmed by comparing its predictions with those of the existing models. This study highlights the potential of machine learning techniques in accurately predicting the moment capacity of flush end-plate connections.

Extended reality (XR) integrates augmented reality (AR), virtual reality (VR), and mixed reality (MR), enabling users to interact with virtual objects and environments as if they were real. XR has found widespread use in civil infrastructure, including design, visualization, worker training, remote collaboration, and maintenance. This paper provides a comprehensive review of the impact of XR on civil engineering and highlights its benefits for design and infrastructure. We conducted our review using articles from conferences and journals. Our review identifies the distribution of XR technology in civil infrastructure, design strategies employed in creating digital technology, and their limitations. Furthermore, our review lays the groundwork for developing the best practices for XR technology in civil infrastructure and suggests future research agendas.

In this study, a semi-analytical method is suggested for the analysis of thin plates. Various methods such as superposition, finite element, and integral transform have been applied to obtain solutions for thin plates. In this study, a simplified method has been proposed through an extension from the classical beam theory to solve plates, which is easier to apply yet relatively accurate. The method uses shape functions obtained from beam solutions having similar boundary conditions. The shape functions are used to approximate the displacement profile of the plate. Galerkin’s method is then applied to obtain the analytical solution of plate deflection. This involves evaluating integrals, which must be computed only once, and the values can be used later. The proposed moment and deflection coefficients are compared with that available in the literature. The results have been compared with previously reported solutions. The maximum error in the case of displacement of a simply supported plate was found to be 1.35% only. The shape functions and the values of integrals corresponding to various boundary conditions have been presented. Plates of various sizes and having various boundary conditions may be analyzed using the proposed closed-form solution for moment and shear. In addition, accurate deflection measurement of thin plates by other methods can be difficult and time-consuming. Therefore, this study explored analytical solutions that may provide a relatively accurate solution for thin plates with comparatively less computational effort.

Steel–concrete composite beams have been widely acknowledged as a highly cost-effective structural solution for multi-storey steel buildings and steel bridges. This paper investigates the behaviour of rebar shear connector embedded in solid concrete slab in composite floor system. A nonlinear 3D finite element model was developed to simulate the push-out test on rebar shear connector, which is a standard test used to determine the shear behaviour of connectors used in composite construction. The shear strength capacity of rebar shear connector obtained from the numerical analysis was compared to the experimental results. A total of eleven push-out test specimens were modelled. The mean value of PFEM/PEXP was found to be 1.0 with a standard deviation of 0.12. The finite element model was also able to simulate experimental failure behaviour of rebar connectors in push-out tests. The simulation models incorporating smaller diameter connectors (10 and 12 mm) exhibited failure primarily due to shearing of the rebar connectors. In contrast, the failure of models featuring 16 and 20 mm diameter rebar connectors was initiated by concrete cracking, subsequently leading to either concrete crushing or connector shearing. The numerical model was also capable of predicting the effect of rebar diameter and concrete strength in shear capacity of rebar connectors as observed in the push-out experiment. The model confirmed that shear resistance increases with larger diameter rebar and higher concrete strength.

The seismic performance of high-rise structures is critical to ensure the safety and structural integrity of buildings in earthquake-prone regions. Engineered Cementitious Composites (ECC) have emerged as promising construction material due to their unique mechanical properties, such as high ductility, strain-hardening behavior, and enhanced energy dissipation capabilities. The addition of Polyvinyl Alcohol (PVA) fibers further enhances the tensile and flexural properties of ECC, making it an attractive option for seismic-resistant structures. This research paper presents a comprehensive study on the seismic performance analyses of high-rise structures constructed with PVA-fibered ECC over conventional reinforced concrete (RC) structures. This study aims to evaluate the effectiveness of PVA-fibered ECC in enhancing the seismic performance of tall buildings under different seismic loading conditions and the variation of PVA fiber and steel rebar percent. A parametric study series is performed using advanced finite element method (FEM) analysis techniques. The high-rise structures with PVA-fibered ECC are subjected to El Centro ground motion records representing different seismic hazard levels analyzed through time history direct integration method considering material nonlinearity and P-delta effect. The response of the structures, including displacements, accelerations, inter-story drifts, and stress distributions, is thoroughly examined and compared to conventional concrete structures. The results of the analyses demonstrate the superior seismic performance of high-rise structures constructed with PVA-fibered ECC compared to conventional concrete structures. The PVA-fibered ECC exhibits enhanced ductility and energy dissipation capacity, effectively reducing the seismic demands on the structural elements.

The torsionally coupled buildings are more vulnerable during strong earthquake ground motions. When a shape memory alloy (SMA) damper is used, the response of structures to lateral and torsional motion is effectively reduced. In this research, numerical investigation is carried out on the seismic response of an idealized single-story asymmetrical frame system with an SMA damper subjected to strong earthquake ground motions. SMA damper restoring force, eccentricity ratio, and lateral and torsional displacements are all variables in this parametric study. The SMA damper-controlled frame’s reaction is measured compared to that of the uncontrolled frame. It is found that the implementation of the SMA damper results in significant reduction in the seismic response of the structure.

Energy-dissipating damper is an effective way to reduce the response of civil engineering structures to earthquakes. Hysteretic dampers are extensively used as energy dissipation device to control the deformation in the structural system. In this direction, shape memory alloy (SMA) has unique re-centering capacity, which shows a flag-shaped hysteretic behavior and offers higher serviceability when used in the building. This research proposed a metallic yielding damper that utilizes this smart metal for creating the shape memory alloy U-shaped Damper (SMA-UD) with a trapezium cross-section. The trapezoidal-shaped U-damper (T-SMA-UD) was compared to the conventional rectangular cross-section under in-plane and out-of-plane cyclic loading. The yield strength, yield force (fy), yield displacement (δy), initial stiffness (K1), post-yield stiffness (K2), stiffness ratio (α), and energy dissipation capacity (Ed) of the suggested and traditional SMA-UD were studied and compared using numerical finite element (FE) analysis. The thickness, height, and width of the T-SMA-UD were adjusted as such that their cross-sectional area remains the same as that of standard rectangular-shaped U-plate damper. The suggested change in shape produced an optimum-shaped U-damper with considerably increased energy dissipation and deformation capabilities compared to that exists in the literature.

The provision of a haunch in beams reduces self-weight, increases shear capacity at support, and enhances joint performance. The present study investigates the seismic performance of reinforced concrete (RC) framed buildings with different numbers of floors: six, nine, twelve, and fifteen floors with haunched beams. Twelve nonlinear static analyses have been conducted to predict seismic performances. Plastic hinges are provided with two ends, a central point of beams, and two ends of columns. The characteristic of plastic hinges of beams and columns controls major axis bending and bi-axial bending with axial compression, respectively. Beams and columns have been considered 2-nodded line elements for the finite element formulations. In most cases, ground floor columns reached the life safety level for the fifteen-storied structure under earthquake excitation compared to RC buildings with a smaller number of floors. In addition, almost 80% of the ground floor beams of the fifteen-storied structure have reached the collapsed prevention performance level. Furthermore, the present finite element-based code used in this study has been validated with the identical model building of previously published work. The difference in results has been found to be (4–5) %, which ensures accuracy and better performance of the present study to enhance this research in the future.

There are various approaches used by different research groups to identify structures and structural changes, and the success of a certain methodology may depend on the context in which it is applied. Therefore, it is crucial to verify promising methodologies by testing them on different structures and damage cases. The objective of this study is to investigate a statistical pattern recognition-based method of Structural Health Monitoring (SHM) using a laboratory structure. Sophisticated finite element models and traditional modal parameters are not used in the implementation of the statistical pattern recognition techniques, as they require significant user interaction. Instead, the statistical approaches presented in this paper are solely based on the signal analysis of the measured vibration data. This makes this approach attractive for the development of an automated health monitoring system. A large-scale laboratory structure was constructed at the Qatar University structures laboratory, and a large dataset of vibration signals was obtained under several structural damage scenarios. This paper suggests a statistical moments-based technique to identify damage using the vibration signals. The method does not require labor-intensive supervised learning, and only acceleration sensor data is required to detect damage. Overall, the proposed approach has the potential to be a cost-effective and efficient solution for SHM of various infrastructures.

Seismic isolation devices are widely used to improve the seismic performance of bridges by mitigating the expected damage. Lead rubber bearing (LRB) is a commonly utilized seismic isolation system, and numerous analytical models of LRB have been proposed in the literature. However, each model has its unique benefits and drawbacks. This research aims to evaluate the seismic behavior of a bridge isolated with LRBs using various LRB modeling methods. A three-span curved steel girder bridge with LRB isolation, which underwent a shake table test at the University of Nevada, Reno, is selected as the reference bridge. A numerical model of the reference bridge is first created and validated using OpenSees. Then, four LRB modeling methods, namely ElastomericX, LeadRubberX, KikuchiAikenLRB, and a novel LRB modeling method, are applied to model the isolation bearings. The new LRB model is developed as a part of this study which has been validated against available experimental results. The evaluation of the seismic behavior of the isolated bridges considers the force–deformation relation of the isolators, bearing shear strain, energy dissipation capacity, and pier shear force. 22 far-field ground motions compatible with the bridge site location have been used to compare the performance of the proposed LRB model with existing LRB models. The comparative analysis reveals that the modeling techniques have a significant impact on the seismic assessment of LRB-isolated bridges. Also, the new LRB analytical model can accurately predict the nonlinear behavior of LRB and subsequently make the seismic assessment of LRB-isolated bridges more accurate.

The joint between a beam and a column is the most vulnerable structure component to collapse during an earthquake. One of the approaches to strengthen the beam-column joint is the application of fibers. A structure’s tension and compression load-carrying capability determines its susceptibility to seismic loads. The use of fiber is known to enhance concrete’s mechanical, flexural, and durability properties for its high tensile strength. Steel fiber, glass fiber, polypropylene (PP) fiber, basalt fiber, etc., and different hybrid fibers are currently being studied to understand their functionality to improve the maximum load, failure pattern, stiffness, hysteretic response, and energy absorption capacity of the beam-column joint when subjected to cyclic loading. This study reviews the influence of fiber volume and their optimum aspect ratio in upgrading these properties through a literature review. Steel fiber has better bridging of wider cracks, and PP fiber limits the micro-cracks; hence, their hybrid form significantly increases the strength and ductility by controlling both macro- and micro-cracks. Carbon and PP fiber are observed to increase the energy dissipation capacity better than other fibers. This review paper outlines that incorporating different fibers can be suitable for strengthening beam-column joints considering engineering properties and economy.

Progressive collapse is the result of a failure of structural components that affect the entire structure, ultimately causing the global collapse of the structure or its significant proportion. The sudden removal of the column increases the bending moment and shear force at the surrounding frames significantly. In this case study, a seven-story frame structure has been investigated under accidental column loss using finite-element (FE) method. In addition to regular loadings, the dynamic load is applied as a time function to simulate the column loss scenario and collapse progression. In the analysis process, one-, two-, or three-column loss scenarios are analyzed to understand dynamic load redistribution and their effect on the global structure. As key parameters of the structure, maximum story drift, displacement, inter-story drift, story shear, base shear, and overturning moments are presented with the time. It is important to note that the building started its permanent deformation after 10 s, approximately. The research found that the vulnerability of the structure escalated as more columns were removed. The affected loading area linked to collapse vulnerability determines the amount of energy the building needed to absorb. The response of the structure also suggested that the damping properties of the structure are also playing a key role in the process of delaying the global collapse of the structure.

The seismic performance study of bridges is critical for any earthquake-prone areas all over the world. The performance-based seismic design of bridge substructures in high seismic zones of an earthquake-prone country like Bangladesh is an important research topic due to the potential impact of earthquakes on the country’s transportation infrastructure. As Bangladesh has no bridge code, bridge designers in our country follow the AASHTO code to design bridges. The purpose of this research is to assess the seismic performance of a constructed bridge in a higher seismic zone of Bangladesh using the AASHTO guideline and the BNBC-defined seismic response spectrum for different tie spacing under different levels of the earthquake. This paper presents the result of the numerical models of the bridges that were designed according to the force-based method for high seismic zone, i.e., Sylhet. The only variable considered in this study is the spacing of transverse reinforcement. The results demonstrate that hinge capacity increases with the decrease of tie spacing. Furthermore, an increase in transverse reinforcement led to a significant improvement in ductility.

In earthquake-prone areas, designing tall buildings that can withstand the ground vibrations caused by seismic activity is crucial. One approach to mitigating these vibrations is through the use of Tuned Mass Dampers (TMDs). This paper presents a multi-objective optimization approach using the NLopt algorithm to design TMDs. The optimization is performed by optimizing the parameters of the TMD located at the roof of different building configurations, with the objective functions of cost and maximum top displacement minimized under two earthquake ground vibration. To support the optimization process, a computer program has been developed in C +  +  linked with the algorithm. Obtained results show that NLopt is effective in optimizing structural performance with a significant reduction in sway and the choice of better TMD parameters under seismic activity. The findings of this study can provide a useful guideline for designers and engineers to optimize TMD parameters and improve the structural performance of tall buildings in a cost-effective manner under seismic activity.

Compared with non-fault-crossing bridges, fault-crossing bridges shall experience relative dislocation on two sides of a fault in addition to dynamic responses. The damage pattern due to such effect can thus be different. A simply-supported isolation girder bridge is simulated and analyzed in consideration of an ideal strike-slip fault. The pounding effect between adjacent girders and between girders and abutment are analyzed. It is found that the relative displacements on two sides of a fault may increase the longitudinal deformation of the isolation bearings. The cross-fault girder shall exhibit in-plane rotating movement. The findings are in accordance with existing laboratory experiments as well as collected bridge damage information from past earthquakes.

Most old structures in Bangladesh are made of poor-quality materials, low-strength concrete (about 15–25 MPa strength), and brick aggregate because of the acute scarcity of natural stones in the early days. The adequacy of these old structures remains a question. Moreover, the updated building code demands a more stringent design philosophy. Therefore, this research aims to investigate the axial behavior of such old columns under concentric loading. The columns are prepared with recycled brick aggregate concrete (RBAC) and compared with new brick aggregate concrete (NBAC) columns. Two concrete strengths are designed using recycled brick aggregate (RBA), such as 17–25 MPa, whereas only 17 MPa concrete is prepared using new brick aggregate (NBA) for comparison purposes. Five square columns of one-third scale with dimensions of 150 × 150 × 950 mm are tested under concentric loading to investigate the behavior of sub-standard brick aggregate concrete columns regarding failure mode, axial capacity, deformation response, ductility, and toughness. The results show that the axial capacity of the 17 MPA NBAC and RBAC columns is similar, but increasing the strength of RBAC columns from 17 to 25 MPa increases up to 32% capacity. Thus, this study will also encourage engineers to reuse recycled brick aggregate (RBA) in reinforced concrete (RC) members by ensuring proper structural detailing.

In aging civil structures, applying fiber-reinforced polymer (FRP) for retrofitting has been found to be effective. However, debonding of it from the structure may lead to catastrophic failure. Some identification methods for FRP debonding locations have been researched recently. In this paper, the method described uses a non-model-based, unsupervised, and output-only method using statistical analysis. Here, only FRP debonding or damage location was investigated; severity was not measured. 3D finite element modeling of an FRP-bonded I-girder bridge is performed in Abaqus. The damage situation has been simulated by the debonding of FRP. The excitation is an impulse load, and consecutive structural responses are collected at specified sensor-mounted points along the bridge span in flaw-induced damaged and undamaged conditions. A second-order statistical moment has been calculated for both sets of data (damaged and undamaged) in the frequency domain. The differences between the statistical moments of the responses of these damaged and undamaged conditions are calculated. The curvatures of these statistical moment differences (CSMD) are calculated and plotted against the sensor position. From the plotted curve, the FRP debonding location has been identified. Different responses’ (displacement, velocity, acceleration, and strain) performance to identify FRP debonding location has also been studied.

Box girder is a widely used bridge system and, consequently, quite common in Bangladesh. The structural capacity of such box girders can be significantly affected during fire exposure due to their thin webs and prestressing tendons. In this study, the thermal behavior of prestressed concrete (PC) box girder sections exposed to both standard and hydrocarbon fire within the interior hollow part has been investigated using the nonlinear FEM software SAFIR. The standard fire has been used to simulate any accidental fire that could occur during the construction or operation phase of a box girder structure. On the other hand, hydrocarbon fire has been applied to simulate an explosion of gas pipelines that could run through the interior of a box girder section. A parametric study has been conducted with varying web thickness and fire duration (ranging between 30 and 240 min) in order to observe the effect of such parameters on the structural capacity of fire-affected box girder section. It has been found that type and duration of fire could have significant impact on the structural capacity of the PC box girder. A preliminary understanding of the effectiveness of a box girder section after a fire event can also be obtained from the outcome of the study. For instance, a web thickness of 200 mm or higher for hollow PC box girder, have been found to be effective for fire exposure considered in the study. However, further investigation with representative fires and variable parameters will be required to develop a comprehensive guideline.

Scour is a common hazard for cross-river bridges and has a detrimental and complicated effect on the seismic behavior of the bridge, e.g., making these bridges more prone to earthquake-induced damage by transferring the damage from columns to piles. The belowground pile damage is difficult to inspect and repair after an earthquake, resulting in a longer-term traffic disruption than their counterparts without scour. Acting as a critical joint in the traffic network, the in-earthquake safety and performance of the bridge are directly related to the traffic capacity of a transportation network after the disaster. In addition, soil-pile interaction modeling and uncertainty modeling are crucial concerns in the earthquake engineering community. Therefore, this study carried out the seismic performance assessment of pile group-supported highway bridges in sandy soil with variable scour effects using the fragility approach. The finite element model for the pile group-supported bridges considering the uncertainty of structural and soil parameters and record-to-record variability is generated. After that, the seismic performance of the bridge with different scour depths is evaluated and compared. The result shows that scour makes the pile group more prone to earthquake-induced damage. The pile group foundation could be changed as the most vulnerable bridge component with the increase of scour depth. However, the scour has a slight influence on the seismic fragility of the bearing and pier.

In this study, the compressive strength of generic concrete and fly ash-based geopolymer concrete (GPC), made of cement by-products, has been compared using appropriate laboratory experiments and fully connected multi-layer artificial neural network (ANN) models. The main objective is to predict the compressive strength by the models and compare the models based on accuracy. ANN is one of the well-known supervised learning algorithms used in the field of artificial intelligence and it can effectively replace the current conventional labor-intensive time-consuming process of laboratory experiments. To prepare the experimental dataset, cylindrical specimens were prepared for generic concrete and GPC. The ANN model takes in fine aggregates, coarse aggregate, and sample size as the input for generic concrete and fly ash, slag, and sodium silicate solution for GPC to predict the output compressive strength based on the dataset used to train the network. All the experimental results and prediction models divulged that the ANN model trained for generic concrete had better accuracy with less error than the GPC one.

Many branches of civil engineering are utilizing the benefit of machine learning (ML) techniques for solving complex problems such as predicting the capacity of fiber-reinforced concrete or steel connections. This paper presents an application of machine learning techniques in bearing strength prediction of self-drilling screw connections in cold-formed steel. Cold-formed steel and its structural forms are getting more popularity and interest from stakeholders because of their easier application, simple fabrication, and lower cost. An experimental database comprising 278 specimens has been developed from the conducted tests and existing literature. The database contains different features of the connections, explicitly end and edge distances, screw diameter and numbers, plate width and thickness, ultimate yield and ultimate strengths of the plates, and pitches along and perpendicular to the loading directions. Three ML-based regression models, namely linear regression (LR), ridge regression (RR), and support vector machine (SVR) are selected for the bearing resistance prediction of screw connections. Those models’ performances are evaluated based on the coefficient of determination (R2), adjusted R2 (Adj. R2), root mean square error (RMSE), and mean absolute error (MAE). The result indicates that SVR performs the best among the proposed models, and the linear and ridge technique performs poorly. Connections bearing strengths predicted by the proposed models are also compared with the existing code-based formulas.

Carbon fiber-reinforced polymer (CFRP) is one of the most promising composite materials for strengthening of aluminum and steel tubular structures. Most of the aluminum tubular member has experienced failure of web crippling under localized compressive concentrated loads. The load-bearing capacity as well as structural performance is reduced due to local buckling of aluminum tubular member subjected to web crippling loading. Externally bonded CFRP strengthening may be considered to overcome this problematic local buckling. The aim of this study is to investigate on improving structural performance and design of aluminum tubular member by CFRP composites under web crippling loading. This study mainly concentrates on the CFRP strengthening effects on aluminum tubular member by CFRP composites under web buckling loading. Using CFRP, a wide-ranging lab testing package were performed under loading of web crippling. A total of 24 aluminum specimens having different slenderness ratio were considered in this research. Load–deflection behavior, the failure loads, and the failure modes have been presented due to concentrated loading. The load-carrying capacity improved significantly and varied 34.6–218% for different slenderness ratio and strengthening technique. ABAQUS software has been used to simulate CFRP strengthening aluminum tubular member of the test results. In this study, geometrical and material nonlinearity was included. Good agreement was achieved between the tested results and the FE simulations. Developed finite element model which is verified with test result is used for parametric study using different sections and slenderness ratios. Design equation for aluminum tubular member using CFRP composites under web crippling loading is proposed. Hence, it can be demonstrated that the improving structural performance can be achieved for aluminum tubular member by CFRP composites strengthening under web crippling loading.

This paper presents an approach to evaluating the post-fire residual capacity of reinforced concrete columns by finite element analysis. Initially developed FE model was validated against an experimental test result. The analysis was performed in two stages: first, fire exposure through thermal response; then, after cooling down, the structural response of the fire-affected specimen to determine the residual capacity. Three different RC square columns with different reinforcement percentages (1, 2, and 3%) were analyzed. Each of these columns was exposed to a standard fire for 60 to 240 min. The outcome from this analysis shows that RC column residual capacity and stiffness decrease as fire exposure duration increases. The results show that for the first 60 min of fire exposure, the residual capacities of all RC columns were 56–68% of their nominal capacities. Among the three column sections, it was observed that the residual capacity degraded faster in cases of columns with smaller cross-section. The residual capacity obtained from FE analysis was finally compared with that calculated using simplified method. From the comparison it was found that, simplified method’s prediction of after fire residual capacities were nonconservative for the RC columns exposed in fire for shorter duration.

Masonry plays a vital role in construction, serving as either load-bearing or infill material in reinforced concrete or steel-framed buildings. In Bangladesh, brick masonry units are commonly used as load-bearing components, especially in rural areas. While capable of withstanding axial loads, brick masonry is not as strong when it comes to resisting lateral loads. With population density on the rise, there has been a trend of using agricultural lands for new building construction, which could be mitigated by vertically extending existing buildings. In this scenario, the capacity of the masonry columns must be increased. To achieve this, various methods can be employed, such as reinforcing the masonry wall using techniques like reinforced concrete (RC) jacketing. The study aimed to investigate the effectiveness of reinforced concrete (RC) jacketing in enhancing the axial compressive strength and ductility of brick columns. The study involved several types of specimens of similar sizes (114 × 114 mm2 before strengthening and 240 × 240 mm2 after strengthening) and four different types of bricks, with RC jacketing used for strengthening. The jacketing utilized 0.70% longitudinal reinforcement, and the specimens have been tested under monotonic loading. The study's results revealed that the axial capacity of masonry columns have been enhanced by approximately 150% with RC jacketing. Additionally, the average ductility enhancement has been found to be 38%. These findings indicate the effectiveness of RC jacketing in enhancing the load-carrying capacity and ability to resist deformation.

Tubular structural members made of steel and aluminum are often prone to structural deficiencies, caused by corrosion and collisions with vehicles or ships, both onshore and offshore. As a result, these degraded members are highly susceptible to severe damage and can lead to the collapse of structures under transverse impact loads. Carbon fiber-reinforced polymer (CFRP) is one of the most promising composite materials for strengthening of aluminum and steel tubular structures. To address these concerns, CFRP has emerged as an attractive and effective solution for strengthening structurally deficient hollow section. The purpose of this study is to examine how CFRP composites strengthen metallic box sections under web impact stress in terms of their structural performance and demeanor. In order to use CFRP composites to strengthen metallic tube members under impact loads, significant test programs have been carried out. A total of twelve box components, eleven CFRP-strengthened members with varying lengths and orientations, and one non-strengthened reference member were tested in a drop hammer impact test system. When subjected to lateral impact loading with a velocity of 4–6.5 m/s, the research's findings offer insightful information. The findings showed that the deformation of mild steel, stainless steel, and aluminum tube sections was reduced by 30.23, 14.18, and 7.40%, respectively, when the box sections strengthened with CFRP were used. The findings show that use of CFRP strengthening enhances the impact resistance capacity of the tubular sections by decreasing side deformations up to 30.23% compared to unstrengthen aluminum tubular specimens. The application of CFRP strengthening is a useful technique for enhancing the performance of structurally flawed steel tubular members under impact loading, according to the experimental results.

Performance-based seismic design approach is implemented to achieve a desired structural performance under a specific seismic hazard level. It requires defining a set of targeted performance levels and their corresponding limits. As current codes and guidelines do not prescribe such limits for different performance levels of bridges with seismic deficiencies such as inadequate ductility and low shear strength, this study aims to develop them. In this paper, quantitative damage states expressed in terms of maximum drifts at various performance levels are developed using incremental dynamic analyses for retrofitted bents. Four retrofit options, e.g., steel, carbon fiber-reinforced polymer (CFRP), concrete, and engineered cementitious composite (ECC) jackets are considered in this study. Concrete and longitudinal reinforcement of all bents cracked and yielded at limiting drifts of 0.06% and 0.38%, respectively. Besides, the ECC jacketed bent experienced core crushing of concrete at the highest limiting drift of 4.16%. The developed damage states can be used for performance-based seismic retrofit design of seismically deficient bridge bents.

Strengthening of RC beam for shear with bonded Carbon Fiber Reinforcement Polymer (CFRP) laminate has been widely used in recent years. However, debonding of laminate from concrete substrate is the main drawback of this method. Various anchorage systems had been investigated to prevent the debonding of CFRP laminate. Embedded bar anchor system could be more effective to mitigate debonding of CFRP laminate. This research aimed to predict bond strength of CFRP laminate with embedded bar anchor through pull-out test of strengthened RC prisms. The effects of widths of CFRP laminate on bond strength were investigated. In the experimental program, a total of 15 RC prism specimens were fabricated. The prism specimens were strengthened using various widths of CFRP laminate. Embedded bar of 6-mm-diameter steel was used as anchors of all strengthened prisms. The specimens were tested under pull-out load to investigate bond strength of externally bonded CFRP laminate with embedded bar anchor. Experimental results showed that the prism specimens failed by debonding of CFRP laminate at laminate–adhesive interface and crushing of concrete rather than debonding at concrete–adhesive interface. The maximum bond strength of CFRP laminate with embedded bar anchor was 3.12 MPa. The average bond strength of 20 mm, 25 mm, 30 mm, 35 mm, and 40 mm widths of CFRP laminates were 3.12 MPa, 2.77 MPa, 2.65 MPa, 2.03 MPa, and 2.25 MPa, respectively. Results also showed that lesser width of CFRP laminate had higher bond strength as compared to larger width of laminate.

In this research, numerical finite element analysis was carried out to study the behavior of steel square HSS columns. The study focused on the effectiveness of reinforcing column sections with CFRP. A 3D FE model was developed using shell elements to represent the square HSS section. Extra layers of shell elements were added to the model to incorporate CFRP strengthening. Material and geometric nonlinearities were taken into account, and composite damage modeling was adopted for CFRP. The developed FE models were utilized to replicate experimental studies conducted by earlier researchers. Numerical analysis and previous experimental findings have shown to be in good agreement, establishing the validity and reliability of the current FE modeling scheme. Further parametric studies were conducted on non-compact AISC square HSS columns to observe the impact of CFRP layer count and cross-sectional shape on the increase of strength. Results indicated that increasing the number of FRP layers enhances column capacity. Further, the study showed that the medium and smaller HSS sections benefit more from CFRP retrofitting than the larger sections. The research in the paper offers a cost-effective way to understand CFRP-reinforced HSS sections. It can help with implementing CFRP retrofitting for steel HSS columns.

Embedded connector has been used as anchor of CFRP laminate in recent years for shear strengthening of RC beam. Interfacial bond strength of laminate is required to design the beam for shear strengthening using externally bonded method. The bond strength mostly depends on width of CFRP laminate for particular strength of concrete. The research aims to predict bond strength of CFRP laminate with embedded connector anchor through pull-out test of RC prisms. In the experimental program, a total of 15 RC prism specimens were fabricated. The prism specimens were strengthened using 20, 25, 30, 35, and 40 mm widths of CFRP laminate. Embedded connector of 16-mm-diameter steel was used as anchor in all strengthened prisms. The specimens were tested under pull-out load to predict the bond strength of externally bonded CFRP laminate. Results showed that all externally bonded CFRP laminate had failed by debonding of CFRP laminate at laminate–adhesive interface. The embedded connector anchor was effectively prevented debonding of laminate at concrete adhesive interface. The maximum bond strength of CFRP laminate with embedded connector anchor was 1.52 MPa. The average bond strength of 20 mm, 25 mm, 30 mm, 35 mm, and 40 mm width of CFRP laminates were 1.512 MPa, 1.417 MPa, 1.52 MPa, 1.14 MPa, and 1.157 MPa, respectively. Results also showed that higher width of CFRP laminate exhibited lower bond strength.