Probabilistic seismic risk and vulnerability assessment framework for RC buildings considering the influence of mainshock-aftershock sequences

To study the seismic risk of reinforced concrete (RC) structures under the action of mainshock and aftershock sequences, an updated seismic hazard quantification model considering mainshock-aftershock sequences is proposed. The proposed seismic hazard model is validated and compared with the mainshock-aftershock sequences (K-NET and KiK net) of the Ishikawa earthquake in Japan (January 2024) and the mainshock sequence of the Wenchuan earthquake (May 2008) in China (696,966 accelerations time histories). A refined structural vulnerability distribution and nonlinear optimization regression algorithm considering the impact of mainshock-aftershock sequences are proposed to obtain a more accurate earthquake risk prediction model for RC building clusters, considering the implications of mainshock-aftershock sequences. A case study and verification analysis of the proposed optimal regression model are conducted using the damage data of 984 RC buildings affected by the mainshock-aftershock of the Wenchuan earthquake, as investigated by the corresponding author. Seismic vulnerability curves of RC buildings in different intensity zones under mainshock-aftershock sequences are generated in reference to the Chinese seismic design code and the basic acceleration values of the design corresponding to different intensity levels. A probability seismic estimation index (PSEI) model considering seismic design standards and basic seismic accelerations is developed to analyze the seismic resistance of RC structures in zones of different intensities under the influence of the mainshock-aftershock sequence. A comparison model of the PSEI of RC buildings with different seismic design levels under the influence of the mainshock-aftershock sequence is generated.