基于推覆分析的RC框架地震倒塌易损性预测

基于倒塌率的结构倒塌易损性分析是目前评价结构抗倒塌能力最合理的方法.但是,目前基于增量动力分析(IDA)的倒塌率分析方法,工作量和实施难度大,很难直接用于工程设计,因此有必要研究便于工程应用的新方法.本文基于18个典型多层RC框架结构的IDA倒塌率分析和静力推覆分析,发现RC框架在大震下的倒塌率及抗倒塌安全储备(CMR)与静力推覆得到的结构位移安全储备之间存在较好的相关关系.依据此关系,建议了保证大震倒塌率的推覆位移安全储备,并通过9个RC框架结构算例进行了验证.本文方法简单易行,可供规则多层RC框架结构抗倒塌设计参考.

Prediction of seismic collapse vulnerability of RC frame based on pushover analysis method

The collapse-vulnerability analysis based on collapse probability is the most reasonable method to evaluate the collapse resistant capacity of structures.However,currently collapse probability analysis is mostly based on incremental dynamic analysis(IDA),which is difficult to be directly used for engineering design due to relatively heavy workload and complicated procedure.Therefore,it is necessary to develop a new method,which is convenient for engineering application.In this paper,18 RC frames are analyzed respectively by using pushover analysis and IDA.Then,the correlation between the results of pushover and those of IDA are studied.The results show that there are fairly good correlated relations between the collapse margin ratio(CMR),the collapse probability under maximal considered earthquake(MCE) and the displacement margin ratio from pushover analysis.Based on these relations,the design displacement margin ratio of pushover analysis to meet the requirement of the collapse probability under MCE is recommended.Nine additional RC frames are used to validate the proposed displacement margin ratio,which shows this method is easy to use and can provide reference for engineering design of regular multistory RC frame.