This study investigates the dynamic soil-structure interaction (DSSI) of a soil-box foundation-12-story reinforced concrete (RC) frame system based on shaking table test data. A three-dimensional finite element model is developed in ABAQUS using the Drucker-Prager model for soil behavior, a master-slave contact algorithm for the soil-structure interface, and the plastic damage model for the RC structure. The numerical results agree well with the experimental data, validating the proposed modeling approach. Parametric analyses are conducted by varying foundation burial depth, superstructure stiffness, additional structural mass, and seismic input characteristics. The results show that decreasing the burial depth reduces the acceleration peak ratio between the foundation top and the free-field soil surface (A1/S10) by up to 4.37%. Increasing burial depth significantly decreases roof acceleration, inter-story shear force, and overturning moment by up to 52.12%, 28.23%, and 49.10%, respectively. These results provide insight into the seismic behavior of DSSI systems and a reliable numerical framework for evaluating soil-structure interaction effects.
The rapid population growth and limited land availability in urban areas have led to buildings being constructed closer to property lines. In such situations, eccentrically loaded footings are commonly adopted at property lines, where settlement and rotational effects become significant. To mitigate these effects, strap beams are provided, connecting the edge footings to an adjacent interior footing and thereby improving overall stability. Conventional analysis assumes column bases to be resting on unyielding support for simplicity and computational efficiency; however, deformable soil conditions necessitate soil-structure interaction (SSI) and structure-soil-structure interaction (SSSI) analyses for realistic and rational solutions. This study investigates a three-storey, 4 & times;4 bay RCC building with eccentrically loaded footings near the property line. Rotation and settlement of footings with and without strap beams are examined under gravity and seismic loading (IS 1893:2025) using ABAQUS software. Four distinct cases are ana-lysed to evaluate the effects of strap beams and SSSI: SSI-E (SSI without strap beam), SSI-S (SSI with strap beam), SSSI-E (SSSI without strap beam), and SSSI-S (SSSI with strap beam). The comparative analysis quantifies the influence of strap beams and SSSI effects on footing rotation and settlement. The results demonstrate that strap beams significantly reduce footing rotation and settlement. Compared to SSI, SSSI leads to increased rotation and settlement at edge footings near the adjacent building. However, incorporating strap beams under SSSI conditions yields amore realistic and reliable prediction of actual footing behavior.
This study presents an experimental investigation on the dynamic and seismic behavior of a reduced-scale steel bridge pier model tested on a shaking table. The model response is first characterized under random white-noise excitations using accelerometers, and the fundamental frequencies are identified through frequency-domain analysis of the measured accelerations. The corresponding damping ratio is evaluated by the half-power bandwidth and the logarithmic decrement methods. The experimentally identified frequencies are then compared with those obtained from a finite element model to assess the consistency and reliability of the numerical simulation. Subsequently, a seismic analysis is performed using the 1995 Kobe earthquake at several intensity levels, allowing the assessment of the structural response under representative dynamic conditions. The seismic response of the model is measured in terms of accelerations and displacements, providing key insight into the underlying dynamic response mechanisms under earthquakes. These experimental measurements are finally used to calibrate the finite element model, with the objective of enhancing the reliability of numerical simulations and improving the predictive capability for the seismic behavior of real-scale bridge structures. The findings contribute to the development of more effective seismic-resistant design strategies and to the reduction of seismic risk in critical civil engineering infrastructures, particularly bridges.
This study develops and evaluates a cantilever-stiffened buckling-restrained brace (CAS-BRB) designed to enhance energy dissipation and cyclic stability while remaining compatible with conventional fabrication practice. A finite element framework was established to simulate a subassembly with a 2.0 m core, incorporating nonlinear steel behavior through combined isotropic-kinematic hardening, low-friction unbonded contact between the core and restrainer, initial geometric imperfections, and a quasi-static loading protocol consistent with seismic qualification practice. A low-yield steel equivalent to HSA80 was adopted for the core, while a conventional structural steel comparable to SS275 was used for restraining and stiffening components. The model was verified by benchmarking against published experimental results and by checking its response against recognized seismic design provisions. Parametric analyses were then conducted by varying the lengths of the welded and cantilever segments to isolate the role of staged engagement during compression. The results show that the cantilever segment delays the onset of strength degradation from the first compressive cycle at 1.5 Delta bm in the baseline case to 2.0 Delta bm for a 150 mm cantilever, while no strength degradation occurs within the applied loading protocol for a 550 mm cantilever. The interaction between the welded and cantilever segments indicates that shorter welded segments require longer cantilever segments to satisfy stability requirements. The welded segment provides the primary compressive resistance, whereas the cantilever segment governs post-contact stability. In addition, the partial-weld detail reduces heat input and residual distortion and is compatible with standard shop fabrication. Overall, the findings demonstrate a practical approach to improving the seismic performance of BRBs and support the development of cyclic qualification procedures and design guidance that link detailing parameters to target performance objectives.
Wire-mesh concrete sandwich walls (WCWs) represent a composite structural system known for its lightweight construction and low-carbon advantages. However, standardized criteria for evaluating their seismic performance remain insufficient, and quantitative assessments of their carbon reduction potential lack rigorous scientific validation-factors that hinder broader engineering application. In this study, incremental dynamic analysis (IDA) and quantile regression were employed to establish, for the first time, a three-tier seismic performance evaluation framework for WCWs based on inter-story drift ratio and inter-story shear force. Furthermore, a novel four-stage correlation model linking seismic intensity measures (IM), structural response, wall dimensions, and carbon emissions was developed to quantitatively relate seismic design parameters to embodied carbon emissions. This model provides a theoretical basis for the integrated design of structural safety and sustainability in green buildings. A case study of a WCW building demonstrated a 41.19% reduction in carbon emissions compared to conventional reinforced concrete shear walls. These findings offer critical theoretical and technical insights for the application of WCWs in sustainable construction.
The welding quality of beam-column joints of steel structures is one of the most important factors affecting seismic behavior of steel structures. In order to investigate the influence of initial defects on the seismic performance of H-shaped beam-column joints, the extended finite element method was used. A crack was set at the lower flange weld of H-shaped beam-column joints, and the influence of defect position and defect depth on the seismic performance was examined. The loading methods with different amplitudes were adopted. The research findings indicate that the initial defect exerts a significant influence on the seismic performance of the joint. The bearing capacity and energy dissipation capacity of the joints were decreased, and the degree of reduction accelerates with the increase of defect depth. However, the loading amplitude has a relatively minor effect on the seismic performance of the joint, with a maximum difference of 6.97% and an average difference of 0.31% in ultimate bending moment. Similarly, the influence of the initial defect location is limited, with a maximum difference of 11.9% and an average difference of 3.6%.
Panelised modular steel structures integrate the merits of high prefabrication integration and low transportation costs, thereby showcasing extensive application prospects in contemporary structural engineering. This study performs a systematic finite element investigation on the seismic behaviour of 16 column-column-beam joints for panelised steel-modular structure, clarifies the influence regularity of key structural parameters (including the wall thickness of the core zone and the arrangement of internal diaphragms) on critical seismic performance indices, and develops a calculation formula for the flexural bearing capacity of the joints along with a theoretical moment-rotation model. The results indicate that for joints with a weak core zone, both the incorporation of internal diaphragms and the thickening of column walls can effectively enhance the mechanical performance of the joints, and the reinforcing effect of internal diaphragms is more prominent. For joints featuring weak angle steels, the addition of stiffeners can significantly improve the energy dissipation capacity of the joints; when the leg thickness of the angle steel reaches a specific threshold, varying the thickness of the beam end plate exerts a marginal effect on the improvement of joint bearing capacity. The deviation between the theoretical values of flexural bearing capacity derived based on the minimum bearing capacity principle and the finite element simulation results is within 8%. Furthermore, the moment-rotation curve model established based on the Ramberg-Osgood empirical formula achieves good consistency with the finite element data. These research outcomes provide a reliable theoretical foundation for the overall performance analysis and engineering design of panelised modular steel structures.
This study investigates the seismic performance of X, K, and Y type joints in a large museum atrium steel-concrete composite structure, under cyclic loading with axial compression ratios of 0.1, 0.2, and 0.3 using China State Construction Zhituo simulation software. The plastic damage characteristics of concrete, stress distribution of steel, and reinforcement cage in each joint during loading are systematically analyzed. Furthermore, the hysteresis behavior of the joints under cyclic loading is examined. The results indicate that with increasing axial compression ratio, the concrete damage in the beam and column core areas of the Y joint is more severe compared to the X and K joints. The steel components effectively limit the deformation of reinforcement in the core area of the joint, satisfying the "strong column weak beam" design principle. The hysteresis curves of all joints are full, with slow stiffness degradation. Meanwhile, the ductility coefficients of the joints decrease with increasing axial compression ratio, indicating weakened deformation capacity. However, the strength degradation coefficient and equivalent viscous damping coefficient increase with increasing loading displacement, demonstrating significant energy dissipation and exhibiting good seismic performance, meeting seismic requirements.
Traditional long-span steel frame structures often struggle to meet the "strong column-weak beam" seismic design principle, with failures typically occurring at column ends. To address this limitation, a novel seismic system integrating a zigzag suspension bridge into the atrium of a large museum was proposed. Three comparative models were established: Model I (standard frame), Model II (frame with suspension bridge), and Model III (frame excluding the atrium truss). Nonlinear time-history analyses were conducted in China State Construction Zhituo simulation software to evaluate roof displacement, interstory drift, base shear, and stress distribution under both frequent (service-level) and rare (safety-level) earthquakes. Under frequent earthquakes, Model II showed a 44.85% reduction in roof displacement and a 35.77% decrease in peak acceleration compared to Model I. This corresponds to a lateral stiffness enhancement factor of approximately 2.20, calculated based on the inverse ratio of peak displacements. Under rare earthquakes, interstory drift angles and base shear were reduced by 67.6% and 30.4%, respectively, further confirming the improved lateral resistance. Notably, the roof displacement was reduced by approximately 1.98 times, indicating a significant enhancement in lateral stiffness. In contrast, Model III demonstrated similar performance to Model II, indicating that the seismic improvement mainly derives from the suspension bridge system rather than the atrium truss. Stress contour analysis revealed pronounced stress concentrations at atrium-frame joints in Model I, implying increased collapse risk. Overall, the zigzag suspension bridge effectively redistributed seismic forces, suppressed structural deformation, enhanced lateral stiffness, and better fulfilled the "strong column-weak beam" design objective for complex public buildings.
Cable-stayed bridges located in seismic-prone regions face durability-related degradation from environmental corrosion throughout their service life and seismic hazards from sudden earthquakes. To investigate this issue, this study uses the Hong Kong-Zhuhai-Macau Bridge as a case study. Nonlinear finite element models for cable-stayed bridges are established at different stages of their service life using OpenSees. The models consider material degradation over time and analyze the time-dependent seismic fragility and earthquake risk of primary components and systems within the cable-stayed bridge. The research findings show that the fragility of diverse components and systems gradually increases as the service life of cable-stayed bridges progresses, although the overall escalation is relatively modest. In extremely rare earthquake, the probability of severe damage and complete failure in seismically-damped cable-stayed bridge systems is significantly lower compared to non-seismically-damped counterparts (48.5% and 24% lower, respectively). Throughout the entire service life, the seismic risk of cable-stayed bridge towers and piers remains below 5%, while the seismic risk of the bridge system is mainly influenced by components with higher seismic risks, such as the bearings. On the other hand, components with lower seismic risks, like the towers and piers, exert minimal influence on the overall risk of the cable-stayed bridge system. The seismic risk of the cable-stayed bridge system remains relatively stable over the full duration of service. Taking the initial service time as an example, the implementation of seismic damping measures results in a reduction of earthquake risk for slight damage by 58.45%, moderate damage by 14.41%, severe damage by 2.52%, and complete failure by 0.32%. It should be noted that these reported risk reductions are relative to the non-damped system and are based on the first-order method, which may overestimate absolute risk. Nevertheless, the comparative effectiveness of dampers is clearly demonstrated. Seismic damping measures significantly enhance the overall seismic performance of the cable-stayed bridge, reducing both its fragility and earthquake risk.
The torsional component and near-fault pulse-like ground motions can bring additional damage to the structure. However, the coupling effect of the abovementioned two factors has not been thoroughly examined in the seismic performance evaluation of base-isolated steel frames. This study examines the individual and combined impacts of torsional and near-fault pulse-like ground motions on the seismic behavior of base-isolated structures. The torsional component record is extracted using the frequency domain approach. A series of base-isolated structures with three length-width ratios are used as case buildings, and the corresponding finite element models are developed using ABAQUS software. A shaking table tests is conducted to validate the finite element model. A comprehensive analysis is carried out on the structural seismic responses. Base shear, floor acceleration, interstory drift, and isolation layer displacement are selected as damage indices for the base-isolated structures. The results indicate that the coupling effect of near-fault pulse-like and torsional components significantly increases the structural seismic response. Additionally, the length-width ratios also bring an obvious growth for structural damage. Specifically, as the length-width ratio increases from 1 to 3, under the combined influence of near-fault pulse-like and torsional ground motions, the floor acceleration increases by 35.85%, 39.75%, and 43.33%, while the displacement of the isolation layer increases by 48.23%, 48.10%, and 49.74%, respectively. The findings point out that ignoring near-fault pulse-like and torsional ground motions would lead to an underestimation of seismic demands in damage assessment.
This paper discusses tsunamis, one of the most destructive natural phenomena, which can cause extensive loss of life and property, particularly in coastal areas. Earthquakes, submarine landslides, volcanic eruptions, and meteorite impacts primarily trigger these events. This study investigates the vulnerability of moment resisting concrete frame buildings in the southern coastal regions of Iran along the Oman Sea, which are at risk of tsunamis generated by the Makran Fault. The primary objective of this research is to evaluate the vulnerability of moment resisting reinforced concrete frame buildings with fixed spans on the first floor-both without openings (featuring enclosing walls) and with openings (lacking enclosing walls) across varying numbers of stories (one, three, and five) under tsunami loading. For this purpose, three-dimensional modeling and analysis were conducted using Siesmostruct software. The analyses included nonlinear static pushover analysis and tsunami fragility (capacity) curves. The structures were modeled based on tsunami design codes from Japan and the United States and tsunami design guidelines. The results from pushover and capacity curves demonstrate that buildings with openings on the first floor (without enclosing walls) exhibit better resistance to tsunami inundation forces than those without openings (with enclosing walls). Additionally, taller buildings are more likely to withstand tsunami forces than shorter structures.
Earthquake vulnerability is a critical indicator for assessing the seismic safety performance of dams. The seismic time history method is a performance-based seismic safety analysis method that can predict the dynamic response of dam structures under different earthquake intensities. To address the issues associated with traditional vulnerability calculations, which require extensive amplitude adjustment and dynamic analysis, this study combines the seismic time history method with traditional vulnerability calculation methods to propose a seismic vulnerability calculation method for earth-rock dams based on seismic time history. First, using the site-specific spectrum, the ETA method is employed to generate seismic time history curves; Then, based on these curves, the dynamic response of the dam under different peak accelerations is calculated; Next, the MSA method is used to compare and analyze the traditional amplitude adjustment calculation method with the seismic time history method to validate the applicability of this method. The calculation results show that the ETA method and the traditional method have high correlation, with the maximum error of the seismic damage index exceedance probability being 15.1%, and the error is within the allowable range. This proves the applicability of the ETA method in the seismic vulnerability analysis of earth-rock dams, and the research results can provide technical references for the seismic performance design and risk assessment of earth-rock dams.
Local shear deformation in structural systems-such as frames and coupled shear walls-has been largely omitted from the classical sandwich-beam formulation, despite its extensive application in the continuous modeling of multi-story buildings. Although several recent studies have attempted to incorporate this mechanism, most available solutions are mathematically complex, limited to specific configurations, and substantially alter the classical model. To overcome these limitations, this study introduces a simple correction factor that incorporates local shear deformation without modifying the classical sandwich-beam formulation, thereby preserving its closed-form analytical advantages. The lateral displacement is decomposed into bending, shear, and interaction components. It is shown that the local shear mechanism does not modify the bending or interaction contributions, allowing existing closed-form expressions to remain valid. However, the global shear displacement requires adjustment through the proposed correction factor, which effectively addresses the large errors documented in previous works. The resulting formulation shows strong agreement with analytical solutions available in the literature and is applicable to both symmetric and asymmetric buildings.
This paper presents a method of evaluating post-earthquake strength of steel moment-resisting frames based on fishbone model using acceleration data. Fishbone model is a simplified frame model used for simulating the structural behavior of steel moment-resisting frames, and it enables to explicitly identify the stiffness parameters of beams and column bases using model updating approaches. First, the stiffness of column bases and beam ends are identified by the model updating method using incomplete modal data identified from acceleration measurements. Then, the strength parameters of column bases and beam ends are calculated based on the identified stiffness values. Thirdly, post-earthquake strength is assessed through Pushover analyses and Incremental Dynamic Analysis (IDA) of updated fishbone models using OpenSees software. Finally, the practical applicability of the proposed method is investigated through the shaking table tests of a large-scale 3-story, 2-bay steel frame specimen. The results demonstrate that the fishbone model not only is competent to predict the accelerations, displacements, and story drift ratios of the structures but also effectively evaluates the post-earthquake strength of the steel frames. In addition, the fishbone model emerges as a reliable alternative to the conventional concentrated plastic hinge model for the assessment of the strength of steel moment-resisting frames after earthquakes.
Soil liquefaction is a key factor leading to building instability and foundation failure during earthquakes. To reveal the influence mechanism of the liquefiable soil layer on surface acceleration response spectra during the "pre-liquefaction" and "post-liquefaction" stages, this study established a 30 m total thickness liquefaction site soil column model using OpenSees. The "surface response spectrum intensity ratio" served as the core indicator to quantitatively analyze the effects of soil layer parameters and ground motions. The results indicate that: (1) Spectra differences between sites are minimal per-liquefaction but become significant post-liquefaction, showing a clear isolation effect. (2) Post-liquefaction site, regardless of the soil layer distribution, the spectra intensity ratios for both short-period (0.01-0.3 s) and long-period (0.8-10 s) ranges are less than 1, reflecting an isolation effect. (3) The spectra intensity ratio increases with the relative density of the liquefiable soil layer and decreases as a power function with increasing thickness and depth. When the thickness ratio (liquefiable soil layer thickness/total soil layer thickness) and depth ratio (liquefiable soil layer depth/total soil layer thickness) are less than 0.1, the growth rate of the isolation effect is the fastest; when the ratios exceed 0.4, the isolation effect stabilizes and reaches its maximum. (4) As the peak ground acceleration (PGA) of the input ground motion increases, the spectra intensity ratio gradually decreases under non-pulse ground motions, while it first decreases and then increases under pulse ground motions. The findings of this study can provide some reference for the seismic design of liquefiable sites.
Near-fault ground motions are often influenced by forward rupture directivity effects, which may generate distinctive long-period velocity pulses and substantially increase seismic demands compared to far-field records. However, conventional design spectra prescribed in seismic codes generally fail to incorporate these near-fault characteristics, potentially resulting in unconservative structural designs. This study examines the spectral amplification associated with near-fault effects and introduces a coefficient-based modification approach derived through regression analysis. A total of 20 ground motion records from the 6 February 2023 Mw 7.7 Pazarc & imath;k earthquake were employed-10 near-fault and 10 far-field-and to account for the bidirectional nature of seismic excitation, both the East-West (EW) and North-South (NS) components were analyzed separately, yielding 40 datasets. Five-percent-damped elastic acceleration response spectra were computed using the Newmark-Beta method across a broad period range, after which average spectra for the near-fault and far-field groups were compared and spectral ratios were calculated to quantify amplification due to fault proximity. The period range was classified into short (T<0.5 s), medium (0.5 s <= T <= 3 s), and long (T>3 s) intervals, and constant amplification coefficients were determined for each category. A regression-based model was further developed to represent the amplification trend as a function of period. An overall spectral modification factor of 1.47 was identified, and when applied to design spectra, this coefficient effectively reduced discrepancies between code-based and response spectra, mitigating potential underestimations. These findings emphasize the importance of explicitly incorporating near-fault effects in seismic design procedures.
The present study addresses the importance of designing buildings to improve their seismic performance, with a focus during earthquakes on how building layouts affect their structural response using nonlinear static pushover analysis. Thirty reinforced concrete buildings of different heights (6, 9 and 12 stories) and aspect ratios ranging from 1 to 10 were constructed using ETAPS 2021 software while adhering to the code guidelines of Algerian Seismic Rules and Eurocode 8. The results after analysis provide valuable insights into the behavioral factors of reinforced concrete structures, which enhances the construction standards to avoid potential risks, with a special focus on evaluating the seismic performance of multi-story structures, which illustrates the role of different designs in the structural response. The results shows that the best seismic performance and the highest shear strength values at the performance point are at small aspect ratios (AR=1 to 3) which result in less displacements, indicating increased stiffness and stability under lateral loads. In contrast, taller buildings with larger aspect ratios showed increased deformation and lower seismic behavior coefficient values, reflecting reduced earthquake resistance. Furthermore, this study gives a comparison between theoretical and seismic behavior factor values of reinforced concrete structures due to sudden constructional behaviors during earthquakes, and stresses the importance of assessing current seismic design rules to address the effect of height and aspect ratio under temblor conditions.
This study investigates the interfacial stresses in composite steel-concrete cellular beams reinforced by composite plates, focusing on their nonlinear behavior. The study examines the impact of adhesive nature and irregular thickness of the adhesive joint on the mechanical performance of the holed beams, examining key parameters such as stiffness, bearing capacity, and stress distribution. Nonlinear elastic theory is used to analyze sliding and linear interfacial stresses in these beams, considering bonded shear deformations and linear shear stress throughout the beam's depth. The study is intended for applications with holed beams made of various materials joined by a thin composite plate. The stresses at the interface are influenced by the material and geometry parameters of the composite beam. The study recommends structural design that balances the size and number of web holes and load-bearing capacity, and recommends using reinforcements around web openings for stability. This research is useful for understanding the mechanical behavior of the interface and designing hybrid structures.
In this paper, a new generalized model of dual-fractional two-temperature nonlocal thermoelasticity is developed to investigate the reflection and dispersion of plane waves in a rotating medium under initial stress. The governing equations of motion, constitutive relations, and heat conduction are reformulated using the Atangana-Baleanu fractional derivatives of two distinct orders, representing two independent memory-dependent heat transport mechanisms associated with the thermodynamic and conductive temperature fields. This framework extends the classical and nonlocal thermoelastic theories by incorporating simultaneous nonlocal spatial interactions and dual fractional temporal relaxation. The combined effects of nonlocality, rotation, initial stress, and fractional orders on the phase velocity, attenuation coefficient, specific loss, and reflection coefficients of longitudinal (P), shear vertical (SV), and thermal (T) waves are analyzed. The results reveal that decreasing fractional orders intensifies thermal memory, enhances attenuation, and shifts reflection peaks, leading to pronounced dispersion and energy redistribution across the boundary. Numerical simulations using aluminum-like material parameters demonstrate strong sensitivity of wave characteristics to fractional parameters and nonlocal coupling, offering new insights into microstructured, rotating, and thermally diffusive materials such as semiconductors and functionally graded solids.
