震损钢筋混凝土框架结构余震韧性分析

In order to evaluate the seismic resilience of a damaged structure for aftershock excitations, a framework of seismic resilience assessment for damaged structures, which was dependent on the mainshock damage states, was developed in this study. The framework was divided into four parts, namely, the selection of mainshock-aftershock sequences, aftershock fragility analysis, the computation of repair time and the determination of the recovery function. For the above-mentioned four parts, the conditional mean spectrum of mainshock and aftershock, the damage-dependent aftershock fragility function based on Logistic regression method, GB / T 38591—2020 ‘Standard for seismic resilience assessment of buildings’ and the characteristic of social resources and rescue capacity were employed to solve the four issues. In order to verify the proposed framework, a seismic-designed RC frame was selected as the case example for the resilience evaluation. The results show that with the increasing of structural damage, the aftershock economic loss of the structure is obviously increasing, and the resilience of the damaged structure is significantly decreased. When the mainshock-induced damage reaches the severe damage state, the decrease rate of structural resilience can be up to 41%, and the increment of economic loss can be as much as 10 times of that of the undamaged structure. There is a nonlinear reduction for the seismic performance when the mainshock damage occurs. Therefore, it is necessary to account for the influence of the current structural damage state in the resilience assessment of a structure.