Bulletin of Earthquake Engineering最新文献

Tall reinforced concrete shear wall buildings used for residential purposes performed well in the 2010 Maule earthquake in Chile. Despite their good performance, in 2011 the regulations governing their design (Ministerio de Vivienda y Urbanismo 2011a, b) were changed to incorporate measures to reduce wall damage by requiring special boundary elements, along with extending the design spectrum to accommodate a broader range of soil types, among other improvements. Therefore, it is now crucial to analyse the performance of RC shear wall residential buildings designed according to the updated Chilean earthquake-resistant design standards and characterise their seismic behaviour in terms of fragility functions. However, different modelling approaches can be adopted for seismic assessment, each involving specific assumptions that significantly influence the building response. This research aims to derive the fragility of typical RC tall shear wall residential buildings in Chile located in a high seismic hazard zone, by analysing the influence of modelling assumptions on the structural response, particularly for the floor system and damping ratio, as these factors have been shown to significantly affect seismic performance. One hundred synthetic ground motion records are used to assess the seismic performance of two representative case study structures (of 9 and 17 storeys) using non-linear time history analyses. Slight, extensive, and complete damage states are selected, and fragility curves are then derived, revealing that models utilizing shell elements to represent the floor system are more efficient and better aligned with the observed behaviour of residential buildings in Chile compared to those using elastic beam elements with rigid diaphragm constraints. Moreover, it is demonstrated that damping ratios are a highly sensitive parameter, significantly influencing the collapse probability of buildings. Therefore, the use of damping ratios from studies that better reflect real-world conditions is recommended. Overall, the results show that the studied buildings do not present a risk of collapse for spectral ordinates less than or equal to 0·5 g.

Advancements in construction material and technology have led to bridge structures with longer spans. The complex finite element models of long-span bridges significantly increase the computational demand and time required for nonlinear time history analysis. Additionally, conventional uniform excitation assumptions, which neglect the intricate spatial variation of earthquakes, are inappropriate for the dynamic analysis of long-span bridges. Against this backdrop, an efficient unconditionally stable explicit KR-α algorithm is employed for structural dynamic analysis and compared with the implicit Newmark algorithm. Meanwhile, the spatial variation of ground motion and soil-structure interaction effect are comprehensively investigated. Initially, a full-bridge finite element model of the Sutong Bridge is developed on the software platform of OpenSees. Subsequently, the structural dynamic analysis and fragility analysis under diverse seismic excitation patterns and constraint conditions are discussed. The results demonstrate that the KR-α algorithm can effectively save the computational time of the long-span bridge without compromising accuracy. Moreover, the maximum difference of damage probability for bridge system between uniform and non-uniform excitations could reach up to 14.7%. Thus, it is suggested to consider the spatial variation of ground motions for the seismic design and assessment of long-span bridges.

This manuscript presents a numerical framework for three-dimensional modeling of arbitrarily oblique incidence of P and SV waves through multilayered soil in time domain for local site effect problems, including soil-structure interaction. The framework consists of two main stages: (i) obtaining the free-field displacement histories at some preselected locations of the layered soil subjected to obliquely incident P-SV waves, using Fourier transform and Stiffness Matrix Method, and (ii) calculating the effective forces acting at these locations by means of Domain Reduction Method, and conducting the finite element analysis in time domain. Results of the proposed framework show good agreements with published studies for a variety of soil profiles, with and without topographical features, in both two- and three-dimensional configurations. Subsequently, the framework was used to analyze a 12-story building rested on a layered soil medium in the scenario of Kobe earthquake. To demonstrate the capability of the proposed framework in dealing with nonlinearity, a soil block underneath the foundation was simulated using a nonlinear hysteresis material model. This example highlights the significant effect of the azimuth angle of seismic waves traveling in three-dimensional spaces on the peak acceleration, peak inter-story drift ratio, and foundation rocking of the building.

Ground Motion Models (GMMs) are empirically-calibrated equations relating ground motion intensity measures to earthquake magnitude, source-to-site distance, geological local site conditions, and possibly other covariates. GMMs are employed for applications such as probabilistic seismic hazard analysis and post-event rapid shaking estimation. Since early 2014, the densely populated Campi Flegrei caldera in Southern Italy has experienced increasing seismicity, concomitant to the volcanic unrest and ground uplift, with over ten thousand recorded events, with duration magnitude larger than − 1.1. In the period between March 2022 and May 2024, seismic activity has intensified, including approximately seventy events with duration magnitudes between 2.5 and 4.4, most of them widely felt, in some cases causing non-negligible seismic structural actions close to the source, and ultimately sparking large public concern. In this study, we calibrated site-specific GMMs for peak ground acceleration, peak ground velocity, and 5% damped spectral pseudo-acceleration for 18 vibration periods (:T) ranging from (:0.02:s) to (:5:s). The dataset includes recordings from the events with duration magnitude greater than or equal to 2.5 over the period 03/22 − 05/24 recorded by more than 50 accelerometric and velocimetric seismic stations at epicentral distances (:{R}_{epi:}<40:km). Moment magnitude, which is the scale used in the GMMs, was derived for the events from their displacement Fourier amplitude spectrum. The GMMs show larger spectral amplitudes at short periods((:T<0.4:s)), and faster attenuation with distance ((:{R}_{epi}ge:5km)) as compared to some existing ground motion models for Italy.

The 2025 (:{M}_{w}) 7.0 Xizang Dingri normal-fault earthquake offers a rare opportunity to evaluate the performance of existing ground-motion models (GMMs) for large normal-fault events ((:{M}_{w}) ≥ 7.0). Using 35 three-component strong-motion records spanning 35–300 km, we assessed four NGA-West2 models and two Chinese regional models (CEA2019, ZB2022). Results show that while NGA-West2 models perform well for low-frequency ground motion parameters (e.g., PSA (T ≥ 3 s)), they systematically overpredict mid- to high-frequency parameters (PGA, PSA (T < 2.5 s)) in both near- and far-field, likely due to differences in source characteristics and strong crustal attenuation in the Qinghai-Xizang Plateau. The ZB2022 model, although calibrated using data from the eastern Qinghai–Xizang Plateau, also exhibits high-frequency (PSA (T < 0.5 s)) overestimation, possibly due to magnitude extrapolation limitations and regional heterogeneity. The CEA2019 model performs well in the near-field but significantly underpredicts long-period motions in the far-field, which may be related to limitations in its modeling methodology. Duration analysis shows both AS16 and WEN18 models underestimate long-duration shaking at far-field. These discrepancies highlight the limitations of existing GMMs in capturing ground motions of large normal-fault earthquakes in Qinghai–Xizang plateau. Our findings emphasize the need for updated regional GMMs incorporating plateau-specific source and attenuation characteristics, particularly for improving ground motion predictions in future seismic hazard assessments.

Highway bridges are often designed with extended pile-shafts due to their cost-effectiveness compared to conventional pile foundations. In contrast to pile foundations that generally remain elastic during earthquakes, extended pile-shafts have similar diameters to columns and are susceptible to localized seismic damage below ground. The complexity stems from column-pile-shaft-soil interactions, variations in soil properties, and bridge-specific design details. This study develops a comprehensive framework to evaluate the seismic fragility of highway bridges supported by extended pile-shafts, advancing the state of the art in several aspects. First, high-fidelity three-dimensional soil-shaft-column-bridge models are developed and validated in OpenSees, enabling the systematic integration of all critical components and capturing multi-directional seismic responses. Second, a two-stage cyclic pushover analysis procedure is conducted to elucidate the column-shaft coupling effect and develop capacity limit state models tailored specifically for extended pile-shafts. Third, uncertainties in bridge attributes and soil profiles are incorporated through Latin Hypercube Sampling, alongside the Kullback-Leibler (KL) divergence measurement to determine the required sample size for reliable fragility estimation. Fourth, for the first time, this study examines the impact of depth-varying ground motions on the seismic demands of different bridge components. Finally, a direct fragility comparison between pile-shaft and pile-group bridges reveals critical differences in stiffness distribution, load transfer mechanisms, and resulting seismic vulnerabilities. Collectively, the developed component- and system-level fragility models provide essential insights for seismic risk assessment, damage inspection, and performance-based design of highway bridges with extended pile-shafts.

The seismic history of a site is the list of earthquake-caused effects that have been observed in a place through time, expressed as macroseismic intensity degrees. A comprehensive review of sources and literature on the effects of earthquakes in Rome is presented in order to reconsider the macroseismic intensities of 15 seismic events that occurred between 1349 and 1979, all catalogued with a local intensity (I) > 5. Notably, the damage effects were georeferenced and overlaid onto historical maps of Rome, contextualizing the impacts within the city’s spatial extent during each earthquake. In total, approximately 500 damage reports were analyzed. For each event, the intensity in Rome was assessed and assigned using both the EMS-98 and MCS scales. Unlike past estimations, the new intensity assessments highlight that very rarely the seismic impact in Rome exceeds the threshold of the degree 6, both for EMS-98 and MCS. Furthermore, it is evidenced that almost all damage observations are related to buildings (monuments, churches, houses) settled within the historical centre. This suggests that Rome’s seismic history pertains primarily to a confined area within the historic center rather than being representative of the city’s current extent, which is approximately up to 30 times larger, depending on the historical period. The revision revealed two main open questions: the estimation of intensity in large urban centers and the homogeneity of the seismic history of a city that has undergone major urban expansion.

Engineered cementitious composites (ECC), as a novel class of high-performance construction materials, are increasingly employed to enhance the mechanical behavior and seismic resilience of structural elements. To further explore the seismic performance of ECC-reinforced beam-column joints, this study develops a computational model to examine the influence of critical design parameters on the seismic response of such joints. Initially, a finite element model of an ECC-integrated beam-column joint (EBC) was established through numerical simulation. The validity and reliability of the numerical model were confirmed by comparing the simulation outcomes with experimental data. Subsequently, the effects of key design variables—including ECC length, strength, thickness, and concrete compressive strength—on the seismic performance of the joints were systematically analyzed. The results indicate that ECC length and thickness have a pronounced influence on seismic behavior. Extending the ECC length from 240 to 640 mm increases the yield displacement by 64.26% and the peak load by 28.65%. Similarly, increasing the ECC thickness from 10 to 50 mm enhances the peak load by 12.83%. However, elevating the ECC strength from 40 to 80 MPa results in only a marginal improvement in peak load capacity, while significantly enhancing the hysteresis performance. The influence of concrete strength on seismic performance is relatively minor. To support practical design applications, a quantitative predictive model (R² = 0.985) and a theoretical shear capacity model (prediction errors < 15%) were formulated. These findings provide meaningful theoretical guidance for the design and optimization of EBC.

Erzurum is one of the major cities in Türkiye with high seismic hazard, having a well-documented history of destructive earthquakes. The June 2, 1859 earthquake (Mw = 6.1) caused severe damage to the city, but no ground motion records exist because it occurred before the instrumental measurement period. This study aims to simulate and validate a simulated ground motion record for this historical earthquake using the stochastic finite-fault method. In this approach, fault geometry, stress drop, crustal properties, and local site effects were incorporated to generate realistic acceleration time histories. The simulated record was validated through comparisons with empirical ground motion models and historical damage reports. For validation, detailed finite element models of Erzurum Ulu Mosque and Murat Pasha Mosque were developed and calibrated using Operational Modal Analysis (OMA) data, and nonlinear time-history analyses were performed to assess the consistency of observed and simulated damage patterns. The findings demonstrate that stochastic ground motion simulations can provide reliable insights into historical seismic events, offering a robust framework for reassessing earthquakes without instrumental records and contributing to the understanding of the seismic performance of masonry heritage structures.

Over the past two decades, the growing demand for housing in Latin America has led to the widespread use of thin reinforced concrete wall buildings (TRCWB) in construction projects. These buildings, particularly those of low to medium height, typically feature wall thicknesses between 80 and 150 mm, reinforced with single or double layers of electro-welded wire mesh (WWM), and sometimes include boundary elements. Both experimental and numerical studies have highlighted limitations of this structural system, including a low capacity for inelastic deformation due to the use of WWM as web reinforcement, and sudden failures caused by concrete crushing and reinforcement buckling concentrated at the wall edges. However, the slab impact on the seismic performance of the system has not been extensively assessed through numerical modeling or experimental analysis, and numerical studies typically use two-dimensional models that do not explicitly consider slabs. This study evaluates the impact of slabs on the seismic performance of low- and mid-rise TRCWB. An analysis of two buildings in Colombia, representing low-rise (5-story) and mid-rise (15-story) structures, was conducted using OpenseesPy. In three scenarios, MVLEM-3D elements were used for walls and shell-type elements for slabs: no slabs, linear slabs, and non-linear slabs. Nonlinear static and response history analyses were employed to assess the seismic response, revealing that models excluding slabs tend to overestimate deformation capacity and underestimate shear capacity by factors between 1.1 and 2.0. The absence of slabs also predicts higher fragility values, especially under severe damage conditions. Interestingly, models with linear slabs produced results similar to those with non-linear slabs, indicating that non-linear behavior is primarily concentrated in the walls. This highlights the importance of including slabs for an accurate assessment of the seismic performance of TRCWB.