考虑主余震序列影响的低延性钢筋混凝土框架易损性分析  

SEISMIC FRAGILITY ANALYSIS OF LOW-DUCTILE RC FRAME ACCOUNTING FOR THE INFLUENCE OF MAINSHOCK-AFTERSHOCK SEQUENCES

作　　者：韩建平[1,2] 李军[1,2] HAN Jian-ping;LI Jun(Key Laboratory of Disaster Prevention and Mitigation in Civil Engineering of Gansu Province,Lanzhou University of Technology,Lanzhou 730050,China;Institute of Earthquake Protection and Disaster Mitigation,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学甘肃省土木工程防灾减灾重点实验室,甘肃,兰州730050 [2]兰州理工大学防震减灾研究所,甘肃,兰州730050

出　　处：《工程力学》2020年第2期124-133,共10页Engineering Mechanics

基　　金：国家自然科学基金项目(51578273);教育部长江学者和创新团队发展计划(IRT_17R51)

摘　　要：主余震序列作用下余震对主震已受损结构会造成附加损伤,甚至引起倒塌,特别是对低延性结构。目前对低延性结构在主余震作用下抗震性能的分析与评估研究还不充分。根据低延性钢筋混凝土框架的破坏特点,考虑其梁柱节点的剪切破坏、柱的弯剪破坏以及强度、刚度退化行为和梁端纵向钢筋粘结滑移破坏,利用OpenSees有限元软件建立了一6层3跨低延性钢筋混凝土框架结构的精细分析模型。选取真实记录的主余震序列和基于重复法构造的主余震序列,并考虑余震方向性、余震次数的影响。以不同的主余震序列作为输入,对低延性钢筋混凝土框架结构模型进行动力分析,获得不同损伤状态对应的地震易损性曲线,进而分析不同主余震序列作用对其抗震性能的影响。分析结果表明,该文提出的低延性结构精细分析模型能很好地模拟低延性结构梁柱节点由剪切作用引起的刚度和强度退化现象。相对于仅有主震作用,主余震序列作用下低延性钢筋混凝土框架结构对应损伤状态的超越概率提高,且随着结构损伤程度的加剧,提高越明显。基于重复法构造的主余震序列作用下对应损伤状态的超越概率高于真实记录的主余震序列作用下的超越概率。不同的余震作用方向,对相应损伤状态的超越概率有一定的影响。增加余震作用的次数,也会增加相应损伤状态的超越概率。Under the action of mainshock-aftershock sequences,the aftershock can cause additional damage to a damaged structure by the mainshock,or even cause it to collapse,especially for a low ductility structure.Currently,the analysis and evaluation of aseismic performance of low-ductile structures under the mainshock-aftershock sequences are not sufficient.According to the failure characteristics of a low-ductile reinforced concrete(RC)frame,the shear failure of beam-column joints,the flexure-shear failure of column,the strength and stiffness degradation,and the bond-slip failure of longitudinal reinforcement at the end of beam were taken into consideration for the numerical simulation of a low-ductile RC frame.The refined analytical model of a 6-story 3-span low-ductile RC frame structure was established via OpenSees finite element software.The real mainshock-aftershock sequences and the mainshock-aftershock sequences based on repeated method were selected.The effects of aftershock directionality and the number of aftershocks were also considered.Taking different mainshock-aftershock sequences as input,the dynamic analysis of the low-ductile RC frame model was carried out and the seismic fragility curves corresponding to different damage states were obtained.Then theeffect of different mainshock-aftershock sequences on its aseismic performance was analyzed.The results showthat the refined analytical model of a low-ductile RC frame presented can simulate the degradation of stiffness andstrength of beam-column joints due to shearing actions.Comparing with the mainshock input only,the exceedanceprobability of the damage state of the low-ductile RC frame under the influence of the mainshock-aftershocksequences is higher,and with the increase of the damage extent under the mainshock,the increase is much moreobvious.The exceedance probability of the corresponding damage state under the influence of themainshock-aftershock sequences based on the repeated method is higher than that under the influence of the realmainshock-afte

关 键 词：主余震序列 低延性钢筋混凝土框架 地震易损性分析 数值模拟 抗震性能评估 

分 类 号：TU375.4[建筑科学—结构工程] TU312.3