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The estimation of the seismic vulnerability of regional structures has contributed positively to the development of seismic risk and resilience in large-scale building clusters. However, the empirical structural seismic damage and ground motion data used to validate the risk model are relatively outdated, resulting in insufficient evaluation accuracy of the established risk model and an urgent use for retrofitting. This study analysed the actual failure peculiarities of typical structures during a recent typical destructive earthquake in China (the Luding earthquake in Sichuan Province on September 5, 2022). A total of 300,000 acceleration records from ten actual monitoring seismic stations were processed and analysed. Nonlinear dynamic time history curves, response spectra, and combined seismic acceleration cloud images were generated considering different directions. Moreover, the traditional instrument intensity calculation equation has been updated, and an instrument intensity curve bunch considering 300,000 earthquake acceleration records has been developed. To study the probabilistic seismic risk of large-scale regional buildings, the developed vulnerability database of typical regional structures (Sichuan Province) was supplemented and optimized, and an updated vulnerability database (413 damage probability matrix) was established, considering the failure of five structures in 32 destructive earthquakes. An updated structural seismic vulnerability model based on extended vulnerability grades was proposed, and a mean vulnerability probability matrix based on structural risk datasets was established. A membership index function for estimating the correlation between different vulnerability grades was innovatively proposed, and the rationality of the model was verified using an improved empirical dataset. A multidimensional failure prediction model was developed based on an improved mean seismic damage index. [ABSTRACT FROM AUTHOR]

Assessing the actual seismic economic losses of regional building portfolios is essential to quantify the seismic resilience of urban and rural areas. Various building clusters indicate different damage levels under real earthquakes of different intensities, which directly leads to apparent anomalies in the actual economic losses of various building portfolios. This paper proposes an economic loss assessment model for large-scale regional building portfolios, considering the damage probability matrices. The traditional empirical vulnerability quantification method is optimized and updated by combining the analysis methods of probability risk, reliability, macroseismic intensity, and instrument intensity. Five typical building sample sets (total survey area: 56,937.1893 × 104 m2) of 57 typical cataclysmic earthquakes that occurred in Yunnan Province, China, from 1993 to 2022 are collected and processed, and an updated fragility dataset is established. The calculation model considering empirical structural vulnerability and economic loss quantitative parameters is innovatively developed. Combined with the quantitative approaches of the multidimensional nonlinear fitting model and the established regional empirical structural vulnerability database, the seismic loss evaluation model of large-scale regional structures is established. Ultimately, the earthquake loss point cloud and matrix of typical building portfolios in the large-scale zone are developed using cloud analysis and the proposed seismic loss evaluation model. [ABSTRACT FROM AUTHOR]

To study the seismic vulnerabilities and performances of typical bridges, data from a field investigation of 2134 bridges on 22 highway sections hit by the Wenchuan earthquake that occurred in China on May 12, 2008, were collected and processed. From the sample data of the empirical seismic-damage observations, 1409 simply supported girder bridges, 107 continuous girder bridges, and 612 arch bridges were selected. The latest version of the Chinese seismic intensity standard was utilized to evaluate the fragility of bridge samples in different macroseismic intensity zones, and the empirical vulnerability matrix and multidimensional regression comparison model of typical bridge clusters were developed. Taking the bridge length, the coordinate azimuth of the bridge location, the number of spans, the geometric form of the pier columns, and the type of bearings and foundations as the single factors influencing vulnerability and assuming (i) the line type and bridge length, (ii) the types of pier column and foundation, and (iii) the number of spans, the type of bearings, foundations, and linearity as the coupled factors influencing vulnerability, the aforementioned typical bridges were subjected to comparative vulnerability analysis. Innovative fragility regression and probability comparison models of typical bridges were developed considering the influence of multiple factor coupling. A novel vulnerability evaluation model was proposed based on the characteristic parameters and damage grade of bridge clusters in the umbrella earthquake area, and the model was optimized and verified by using the typical bridge database of the Wenchuan earthquake. [ABSTRACT FROM AUTHOR]

The seismic vulnerability of regional buildings is a fundamental index to effectively predict and estimate the seismic resilience of urban and rural areas. The structural empirical vulnerability database can be used to develop and generate relatively accurate multidimensional vulnerability models. With the development of instrument intensity and the updating of macroseismic intensity scales, the structural vulnerability assessment model established using the traditional regional structural empirical vulnerability database shows features of low accuracy. Therefore, using innovative methods to update the conventional vulnerability estimation model has become a fundamental scientific problem to be urgently solved. In this study, the mixed effects of instrument intensity and macrointensity and their evaluation scale were sufficiently considered, and the traditional vulnerability level quantification scale was improved. The structural empirical vulnerability database of three typical earthquakes in China (Wenchuan in 2008, Yushu in 2010, and Jiuzhaigou in 2017) has been comprehensively updated, and the multiscale statistical and computational model has been developed. A nonlinear regression model based on multidimensional vulnerability quantification parameters was proposed. A comparison model for predicting the actual seismic vulnerability of four types of buildings considering typical earthquakes was developed. The traditional vulnerability index algorithm was updated, and the point cloud and strip domain quantitative model based on the updated empirical vulnerability database (27,394 buildings) was established. • A vulnerability assessment model based on updated intensity measures is proposed. • The former empirical vulnerability database has been updated. • The traditional calculation method of the vulnerability index is improved. [ABSTRACT FROM AUTHOR]