钢筋混凝土框架结构的损伤状态相关余震易损性分析  

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

作　　者：于晓辉[1,2] 周洲 吕大刚 YU Xiaohui;ZHOU Zhou;LÜDagang(School of Civil Engineering,Harbin Institute of Technology,Harbin 150090,China;College of Civil Engineering and Architecture,Guilin University of Technology,Guilin 541004,China)

机构地区：[1]哈尔滨工业大学土木工程学院,黑龙江哈尔滨150090 [2]桂林理工大学土木建筑工程学院,广西桂林541004

出　　处：《建筑结构学报》2022年第4期8-16,共9页Journal of Building Structures

基　　金：国家自然科学基金项目(51778198,51678209)。

摘　　要：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回归方法生成余震易损性曲线。基于余震易损性,进一步计算余震损伤状态跃迁概率和余震易损性指数来评估震损结构的余震安全。为了进一步说明所提方法的合理性,选择一栋按我国规范设计的5层钢筋混凝土框架结构为研究对象,选取一组真实主余震序列作为输入,生成了结构的损伤状态相关的余震易损性曲线。分别考虑余震危险性水平为结构抗震设计的多遇地震、设防地震和罕遇地震水平,计算了结构的余震损伤状态跃迁概率矩阵和余震易损性指数。分析结果表明:所提出的方法可以有效揭示余震易损性对主震损伤状态的依赖性;随着主震损伤的提高,余震发生更严重破坏的概率显著提高;余震损伤状态跃迁概率和余震易损性指数可以定量评估震损结构在不同危险性余震作用下的安全性。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.

关 键 词：钢筋混凝土框架结构 主余震序列 损伤状态相关 地震易损性 余震安全 

分 类 号：TU375.4[建筑科学—结构工程] TU311.41