Bulletin of Earthquake Engineering最新文献

This study investigates the effects of adjacent deep excavation on the seismic performance of buildings. For that purpose, the numerical models are constructed for different buildings (i.e., 5-Story building and 15-Story building) considering the deep excavation-soil-structure interaction (ESSI) and soil-structure interaction (SSI). The results achieved from the ESSI and SSI systems are discussed and compared. Fully nonlinear numerical models with material, geometric, and contact nonlinearities are developed. Eleven earthquakes with different intensities, epicentral distances, significant durations, and frequency contents are applied to the models; and, the numerical results are given in terms of average records. The buildings are carefully designed and verified based on common design codes. The numerical modelling procedure of the deep excavation-soil system is validated using centrifuge test data. The comparisons between the ESSI and SSI systems are carried out in terms of accelerations, lateral displacements, inter-story drifts, story shear forces, and the nonlinear behavior of the soil medium under the buildings. The results show that it is necessary to consider the ESSI effect, and it might significantly change the seismic behavior of buildings adjacent to the deep excavations. The findings from this study can provide valuable recommendations for engineers to design buildings close to deep excavations under earthquakes.

Non-structural elements play a crucial role in the overall seismic performance of buildings, as has been largely demonstrated in recent earthquakes that have stuck densely populated regions. Therefore, the development of performance-based seismic design and assessment methodologies for non-structural elements is becoming an important research topic within earthquake engineering. A crucial aspect in such methodologies is the accurate prediction of the seismic demands acting on non-structural elements in terms of consistent absolute acceleration and relative displacement floor response spectra for the most common types of structural seismic force resisting systems. Masonry-infilled reinforced concrete frames are one of the most common building typologies in high seismicity regions, such as the Mediterranean region. This study proposes a simplified procedure to estimate consistent absolute acceleration and relative displacement floor response spectra in masonry-infilled reinforced concrete frames based on an existing methodology to estimate consistent floor response spectra in bare reinforced concrete frames. Nine archetype masonry-infilled reinforced concrete buildings with different numbers of storeys and arranged with three masonry infill typologies were considered as case-study archetypes, and were used to validate the proposed methodology using nonlinear time history analyses. The proposed procedure can accurately estimate consistent absolute acceleration and relative displacement floor response spectra for masonry-infilled reinforced concrete buildings that respond both in the elastic and nonlinear ranges for all the non-structural period range. The estimates of floor response spectra given by the proposed procedure are fully consistent with the well-known pseudo-spectral relationship for the entire non-structural period range.

Zhuanyao dwellings faced significant seismic risks in rural regions of China. Therefore, a shaking-table test was performed to explore the seismic performance of Zhuanyaos and validate the finite-element simulation results. The results showed that the damage to the pier and roof levels of Zhuanyaos was more severe after earthquakes, resulting in a noteworthy increase in the displacement responses of these two levels compared to that of the vault level. The damage to the front structure (Yaolian) and mid-pier of the Zhuanyao were more severe than the damage to the back wall and side pier, respectively, which caused a significant reduction in acceleration responses of Yaolian and mid-pier. Following the crack development, dynamic response, and field investigation, three typical collapse modes of Zhuanyaos were presented. Subsequently, the parametric analysis was conducted using a verified finite-element simulation method. The results show that using the catenary arch can reduce earthquake damage in Zhuanyaos. Increasing the width of the middle pier can improve the seismic performance of Zhuanyaos to a certain extent; however, it may exacerbate local damage to the structure. Besides, the high seismic vulnerability of Zhuanyaos stemming from an increasing thickness of overlying soil cannot be ignored.

Nonstructural components (NSCs) are elements within the building unrelated to the lateral load-carrying system. Failure of NSCs during earthquakes can result in casualties, significant economic losses, disabled critical infrastructures, and loss of building functionality. The NSCs can be categorized into two primary groups: deformation-sensitive and acceleration-sensitive. Thanks to well-established seismic design guidelines and standards, buildings may suffer minor seismic deformations – resulting in lesser damage to deformation-sensitive components. However, planning under the peak floor response or peak floor acceleration (PFA) is getting much less attention – exposing the acceleration-sensitive components to greater risk. This manuscript develops equations for moment-resisting reinforced concrete frames (MRRCFs) that estimate the total floor acceleration. The data is gathered based on 984 inelastic response simulations, elaborated to create an idealized equation based on the earthquake characteristics. The developed equation offers engineers a quantitative approach to understanding the inertial forces applied to the NSCs within the building during earthquakes, allowing them to plan for potential risks due to earthquakes.

We present the results of probabilistic seismic hazard assessment for Iran based on a statistical procedure specifically developed to manage macroseismic intensity data. This method takes into careful consideration the specific features of such data, which are characterized as ordinal, discrete, and confined within a finite interval, ensuring a logically coherent approach throughout the analysis. The results of our assessment are then compared with hazard maps generated using a standard approach, putting in evidence significant differences both on a national scale and relative to individual cities. This comparative analysis will be useful in identifying areas of utmost concern, where further studies are strongly recommended to yield hazard estimates of greater robustness and reliability. By pinpointing these critical scenarios, we aim to guide future research endeavors towards providing more accurate and reliable seismic hazard estimates. Identifying these critical situations facilitates the prioritization of resources and interventions, ultimately enhancing seismic risk mitigation efforts across Iran.

The establishment of acceptable risk standards serves as a crucial connection between earthquake disaster risk assessment and risk management. Currently, there lacks a standardized criterion for determining the acceptable level of risk pertaining to earthquake disasters. To establish a standardized system of acceptable risk of earthquake disaster, the data of disaster-affected toll, death toll, and direct economic losses resulting from earthquakes disaster with M_S ≥ 5.0 in Chinese Mainland between 1991 and 2020 are utilized. These data are employed to construct the acceptable life risk F–N curve (the accumulated probability F of annual death toll ≥ N—death toll N), the acceptable economic risk F–D curve (the accumulated probability F of annual direct economic losses ≥ D—direct economic losses), and the acceptable comprehensive risk F–L curve (the accumulated probability F with earthquake occurrence of annual disaster degree ≥ L—disaster degree). Then, the acceptable risk level of earthquake disasters with M_S5.0–5.9, M_S6.0–6.9, M_S ≥ 7.0, and M_S ≥ 5.0 are determined. Moreover, the classification and consistency of acceptable types of earthquake disaster comprehensive risk, life risk and economic risk in the past 30 years are compared. Through analysis, the acceptable life risk, acceptable economic risk, and acceptable comprehensive risk criteria of earthquake disasters with M_S5.0–5.9, M_S6.0–6.9, M_S ≥ 7.0, and M_S ≥ 5.0 in Chinese Mainland are obtained. It is found that the comprehensive risk of earthquake disasters with different magnitudes is mainly at an unacceptable level, while the main types that are consistent with life risk and economic risk are tolerable level and acceptable level, respectively. The research results can provide more comprehensive theoretical data and practical basis for the effective implementation of earthquake disaster risk management.

This study presents a comprehensive seismic hazard assessment for Büyükçekmece, a district in Istanbul, Turkey, situated near the seismically active North Anatolian Fault (NAF). The study utilizes stochastic ground motion simulations with the validated EXSIM algorithm to understand the potential impact of medium to large-magnitude earthquakes (ranging from M_W 6.3 to 7.42) on this vulnerable community. The research employs a site-specific approach, considering unique amplification factors for each location. By conducting 50 scenario-based simulations, the study assesses the seismic hazard, highlighting the importance of comprehending variations in ground motion, even when they are small, for a more precise hazard assessment. Furthermore, this study addresses the critical issue of uncertainty, particularly concerning stress parameters and hypocenter locations. The researchers demonstrate that variability in these factors can introduce substantial uncertainty in ground motion predictions. The study provides insights into the range of potential ground motion outcomes through probabilistic assessments involving multiple scenarios and stress drop values. Notably, the results indicate that ground motion levels vary with earthquake magnitudes and underscore the significance of accounting for this variability. This research emphasizes the seismic vulnerability of Büyükçekmece and the importance of accurate ground motion simulations, offering valuable insights for earthquake preparedness and mitigation efforts in the region.

In Iceland, the most seismically active region in Northern Europe, large earthquakes up to ~({M}_{text{w}})7 repeatedly take place in the two transform zones of the country. Of the two, only the South Iceland Seismic Zone (SISZ) in southwest Iceland is on land and with a large part of the country’s population either collocated or in close proximity to it. Strong earthquake occurrence in the SISZ takes place on a bookshelf fault system, an array of short, vertical, and dextral strike-slip faults oriented perpendicular to the overall transform motion. Importantly, this system has recently been shown to be continuous further towards the west along the entire Reykjanes Peninsula Oblique Rift (RPOR), making the bookshelf fault system approximately twice as long as previously thought. Moreover, a systematic spatial variation of maximum earthquake magnitudes characterizes the SISZ-RPOR system, from ~({M}_{text{w}})7 down to ~({M}_{text{w}})5.5 from eastern SISZ to western RPOR, respectively, indicates a subzonation of the seismic region. The above has not been taken into account in past probabilistic seismic hazard assessments (PSHA) and poses a challenge as the historical earthquake catalogue precludes reliable estimates of seismicity parameters for individual subzones of the SISZ-RPOR system. In this study, we address this issue using a recently developed physics-based finite-fault model of the SISZ-RPOR bookshelf fault system, and quantitatively estimate the time-independent magnitude-frequency distributions (MFDs, of the Gutenberg-Richter type) for each subzone. We establish zone-specific distributions representative of long-term fault slip rates and derive the seismicity parameter estimates corresponding to the 2.5, 50, and 97.5 percentiles of fault slip rates along the SISZ-RPOR as predicted by the physics-based model. We present new and quantitative estimates of subzone MFDs and show that the model effectively explains the historical earthquake catalogues. The results of this study not only enable the efficient yet physically realistic and consistent revision of conventional time-independent PSHA for southwest Iceland using e.g., empirical ground motion models, but also a more comprehensive physics-based PSHA from finite-fault rupture modeling and advanced seismic ground motion simulation techniques.