钢筋混凝土框架结构的损伤状态相关余震易损性分析

一次主震过后通常伴有多次余震发生,由于主、余震间隔时间较短,主震损伤结构通常要遭受进一步的余震作用.为了评估震损结构的余震安全,提出了一种损伤状态相关的余震易损性分析方法.该方法采用有限次整体调幅的主余震序列作为输入,利用Park-Ang指数描述结构在主余震序列作用下的主震损伤和累积损伤,基于logistic回归方法生...

Damage-state-dependent aftershock fragility analysis for reinforced concrete frame structures

A mainshock is typically followed by several aftershocks. Due to short intervals between the mainshock and the following aftershocks, the mainshock damaged structure usually suffers the further aftershock. To evaluate the aftershock safety of the mainshock damaged structure, a damage-state-dependent aftershock fragility analysis approach was proposed. Globally scaled mainshock-aftershock sequences were adopted as earthquake inputs. The Park-Ang damage index was used to describe the mainshock damages and accumulative damages under earthquake sequences. The aftershock fragility curves were developed using logistic regression. Based on the developed aftershock fragility curves, the increasing probability in aftershock-induced damage state and the aftershock vulnerability index were calculated to evaluate the safety of the mainshock-damaged structure under aftershocks. To illustrate the proposed method, a 5-story RC frame designed according to current Chinese codes was taken as the study case. A suite of real mainshock-aftershock sequences were taken as the earthquake inputs. Then the damage-state-dependent aftershock fragility curves were developed. Considering the aftershock intensities corresponding to the frequent, fortified and severe earthquake hazard levels, the increasing probability matrix in aftershock-induced damage state and the aftershock vulnerability index were determined. The results show that the proposed method can effectively reveal the dependence between aftershock fragility and mainshock damage states. With the growing mainshock damage, the probability of structures suffering more serious damage under aftershocks is significantly progressed. The increasing probability in aftershock-induced damage state and the aftershock vulnerability index can quantify the safety of the mainshock damaged structures under different aftershock hazards.