Bulletin of Earthquake Engineering最新文献

The quantitative relationship and underlying mechanism between earthquake-induced porewater pressure (PWP) changes and ground motion characteristics remains an unresolved issue in earthquake engineering. This study aims to quantify this relationship by analyzing downhole array data from two sites, which includes ground motion measurements and high sampling rate PWP records. Both time-domain and frequency-domain analyses were conducted to characterize PWP oscillation under various shaking conditions. The results revealed a strong correlation between the PWP fluctuation and vertical ground motion in terms of their amplitudes and frequency contents. This is because vertical motions, mainly composed of compression waves, induce instantaneous contraction or dilation in soil. Consequently, two analytical models grounded in wave propagation and poroelastic theory, and validated through field observations, were proposed to estimate peak PWP changes using ground motion parameters.

Contemporary pavement analysis research seeks to enhance previous methodologies by applying an intricate 3D Finite Element Method (FEM) model within a multi-physics framework. The primary aim is to more precisely depict soil behaviour utilizing Pasternak foundations, which enhance the basic Winkler models. This methodology facilitates an exhaustive examination of the dynamic variables influencing jointed reinforced concrete pavement (JRCP) at airports subjected to multidirectional seismic stresses. The reliability of these FEM JRCP models is confirmed by comparison with previous research and a mesh convergence analysis. Upon Validation, the model evaluates the influence of the sub-base modulus, subgrade modulus, and concrete grade of the pavement slab on its dynamic performance. This analysis utilizes seismic data from the Uttarkashi earthquake (magnitude M 6.6) as the input for ground motion modelling. A statistical sensitivity analysis was used to establish generic design principles for airport JRCP pavements. The research indicated that increased concrete stiffness results in enhanced transverse displacement of the pavement during seismic stress. Moreover, superior-grade concrete can withstand elevated Von Mises stresses before fracturing. A more substantial sub-base was determined to reduce transverse displacement, thereby enhancing lateral support during seismic events. Ultimately, augmenting the subgrade stiffness was demonstrated to reduce deflections and to improve load distribution, hence diminishing the Von Mises stress in the concrete slab.

This study proposes a comprehensive data-driven framework for quantifying seismic fragility and performance degradation in historical masonry pagodas. Leveraging shaking table tests on 1:8 scale models of the Small Wild Goose Pagoda in both intact and damage-inclined states, a high-resolution dataset ( > 1000 samples) was constructed, capturing key seismic responses—peak acceleration, displacement, and interstory drift—under multidirectional and multi-intensity ground motions (PGA: 0·15 g–0·60 g). A multi-model machine learning pipeline combining Random Forest, XGBoost achieved high predictive accuracy (R² > 0.90), while SHAP-based interpretability analysis identified ground motion intensity, story height, and damage state as dominant predictors. Fragility curves revealed a pronounced vulnerability increase for the damaged model, with a leftward shift in exceedance probabilities. A multi-task CatBoost model with split-conformal calibration provided reliable uncertainty-aware predictions, supporting risk-informed decision-making. Further, a binary classifier (AUC = 0.928) enabled effective post-earthquake condition identification, while response ratio analysis quantified residual capacity loss, particularly in interstory drift. The proposed interpretable and uncertainty-quantified framework advances seismic risk assessment and resilience planning for heritage masonry structures.

Column-supported grain silos are vital for food security but are notoriously vulnerable to earthquakes. A robust framework for assessing their seismic risk is lacking, especially one that accounts for the coupled effects of inter-silo interaction in group configurations, stored material dynamics, and the distinct hazard of pulse-like near-fault ground motions. To address this, we developed a high-fidelity finite element modeling approach, with its dynamic characteristics rigorously validated against shaking table experiments and simplified analytical models. A large-scale probabilistic vulnerability assessment was then performed using Incremental Dynamic Analysis (IDA), with the elastic-plastic column drift serving as the primary damage indicator. Our findings establish that ground motion pulsatility and storage level are the primary drivers of seismic risk. Pulse-like motions consistently increase failure probability; at a design-level PGA of 0·4 g, the collapse risk for a fully loaded row silo rises from 46% (non-pulse) to 52% (pulse). The fully loaded state is unequivocally the most hazardous condition due to amplified inertial forces and dynamic material pressures. Interestingly, the interconnected nature of row silos presents a state-dependent trade-off, offering marginal performance benefits when empty but exacerbating vulnerability compared to single silos when fully loaded. This research provides a new systematic fragility comparison for single versus group silos, delivering validated models for performance-based design and underscoring the urgent need to revise seismic codes to explicitly account for the severe, quantifiable threats posed by near-fault pulses and operational storage levels.

The evaluation of post-earthquake functional recovery of buildings is pivotal for seismic resilience assessment and underpins resilience-oriented seismic design. This study proposes a generalized method that can predict the potential functional recovery trajectory of any occupancy type of building. This method distinctly models delay time and repair time. Delay time accounts for the duration required for building mobilization activities and the recovery of utility systems to full functionality. The triggering conditions for mobilization activities are clarified by component damage severity and the repair cost ratio of buildings. The repair time is modeled by embedding the critical path method into an Activity-on-Edge network, incorporating the procedure importance coefficient under limited floor space to optimize labor allocation, thus achieving dynamic coupling of repair processes and labor resource scheduling. Utilizing Monte Carlo simulation as the underlying mechanism, the method enables probabilistic modeling of the functional recovery trajectory and subsequent calculation of the seismic resilience index. A case study of a teaching building demonstrates the method’s efficacy in pinpointing critical recovery bottlenecks, optimizing labor allocation, and delivering recovery trajectory simulations. It exhibits robust adaptability and scalability, providing an effective analytical tool for seismic resilience assessment, enhancement, and design across diverse occupancy types of buildings.

Accurate estimation of the seismic demand of buildings requires carefully considering both the ground motion group size (n) and the angle of seismic input (ASI). Existing studies focus more on the relative effect of either n or ASI on evaluation results. There is ongoing debate on the n and ASIs required in deterministic and probabilistic seismic performance assessments, and no specific guidelines have been established for engineering practice. To address this concern, this study proposes a framework for assessing statistical bias of response and providing engineering-oriented recommendations for n and ASI in nonlinear response history analysis of mid-rise buildings. Firstly, a regrouping procedure is presented to generate 100 suites of ground motions with a specified smaller size of n from a benchmark large dataset of ground motions. Next, three statistical indices are defined to precisely characterize the bias between the small-sample and benchmark large-sample ground motions, namely bias(µ), sdev(µ), and bias(β), which quantifies the effects of n and ASI on errors of the estimated central tendency and variability of response in deterministic and probabilistic analyses. Based on an acceptable statistical bias, the required values of n and ASI for different conditions are recommended. Finally, to facilitate practical application, a simple yet efficient model of the correction coefficient (κ) of variability is proposed to save computational time and improve assessment accuracy. Results show that at least 10 pairs of records and 4 input directions are required to ensure reliable estimates of expected seismic response for mid-rise buildings. The bias in variability can be adjusted using the κ. These engineering-practical recommendations contribute to resolving the ongoing debate regarding the necessary n and ASI in seismic performance assessments of mid-rise buildings.

Tunnel-form buildings represent the main typology used in mass housing projects in Türkiye, with their heights continually increasing to meet the rising demand for land. Research has shown that low- and mid-rise tunnel-form buildings performed satisfactorily even under earthquake ground motions exceeding their design intensity. However, only a limited number of studies examined the performance of high-rise tunnel-form buildings. These structures are characterised by inherent vulnerabilities due to the use of lightly reinforced slender shear walls and conventionally reinforced squat coupling beams as primary structural members. The present study numerically examines the seismic performance of such structures and offers recommendations to enhance their design. A 14-storey tunnel-form building, representative of a large percentage of mass housing projects across Istanbul, is selected for case study purposes. A state-of-the-art three-dimensional non-linear finite element model is created in OpenSeesPY. Prominent failure modes of the components are incorporated into the model. The modelling strategy is validated at the component level using experimental results and at the system level using the results of ambient vibration tests conducted on an existing building. Standard and multi-mode adaptive pushover analyses are used to provide insights into the evolution of damage and define a damage scale. The seismic performance is evaluated through a Multiple Stripe Analysis procedure, and fragility functions are derived at both component- and system-levels. The fragility analysis shows that high-rise tunnel-form buildings have a very high probability of providing life safety even in very rare, high-intensity earthquakes. However, immediate occupancy of the building is likely to be jeopardised due to the severity of the incurred damage. The study offers several insights into the seismic performance assessment of such structures and provides guidance on how to improve their design.

This study investigates the evolution and current status of seismic design regulations in Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, and Venezuela, using a pre-established methodology previously applied for Europe. It introduces a simplified methodology to estimate the proportion of buildings designed under four seismic code levels: no code, low code, moderate code, and high code. By analysing the progression of seismic design standards across South America, the study determines lateral force coefficients for a typical mid-rise reinforced concrete structure corresponding to each seismic code level. The findings reveal that approximately 20% of the total building stock, and 55% of reinforced concrete buildings, were constructed while regulations with some seismic provisions were followed. This research offers essential tools to enhance seismic risk assessment models and provides a dynamic framework for integrating new data, technological advancements, and local expertise into exposure modelling. Furthermore, it contributes to a global initiative led by the Global Earthquake Model (GEM) Foundation aimed at improving accessibility to information on seismic regulations and seismic hazard design demand maps.

Seismic Microzonation studies aim to map and determine the seismic ground response and the susceptibility to instability phenomena, such as liquefaction, landslides or surface faulting. According to Italian government laws, seismic microzonation is evaluated following three Levels of detail (I, II and III), with increasing complexity. In areas susceptible to instability phenomena, in-depth investigations typical of Level III are necessary to verify the safety conditions. In this framework, the liquefaction potential was evaluated for a zone prone to seismically induced liquefaction located on the eastern Sicily (Italy). The stress-based method was employed to evaluate the susceptibility to seismic-induced liquefaction considering the results derived from Dynamic Probe Super Heavy tests. They have the advantage, compared to Standard Penetration Tests, of providing continuous values with depth. Three different approaches were used to define the seismic action: the simplified approach proposed by the Italian seismic code, the selection of a suite of ground motion records and the definition of a combination of synthetic seismograms reproducing the 1908 seismic event. The results show that the use of a suite of ground motion records compatible, on average, with the target spectrum built according to the Italian seismic code, is conservative compared to the other two approaches. Furthermore, the level of liquefaction severity encountered in the investigated area is high, demonstrating the need for mitigation actions. The findings obtained in this study allow to optimize the allocation of economic resources and are useful for future similar works.

The Applied Element Method (AEM) has in the recent years been increasingly employed to assess the failure mechanisms developed by structures subjected to dynamic loading. However, its use in the detailed estimation of local response parameters such as strains, curvature, and other localised deformations of reinforced concrete (RC) elements under seismic excitation, is not common. In this context, we explore the feasibility of using the AEM to reproduce, in blind-prediction fashion, the recent shake-table axial-flexural-torsional response of a 40-ton half-scale reinforced concrete U-shaped wall specimen. The accuracy of the adopted modelling approach in capturing the experimentally observed translational-torsional structural response of the tested structure is demonstrated through the comparison between numerical predictions, obtained before the publication of the test results (and thus without post-test model improvements), and the experimental measurements, considering both global and local response quantities. On a somewhat separate note, this study also examined the manner in which currently available formulations are capable of estimating residual drifts in RC walls, and proposes an updated equation that is shown to predict, with a good degree of accuracy, post-earthquake shaking residual displacements for this type of structures.