主余震作用下高强钢筋混凝土框架的易损性分析

为研究主余震作用下配置高强钢筋的RC框架结构的抗震性能，根据相同设计指标和"等强代换"的原则，设计了三榀六层四跨的钢筋混凝土框架，纵向受力钢筋的强度等级分别为HRB400、HRB500和HRB600。通过OpenSees平台进行有限元建模，将最大层间位移角作为结构损伤指标，反应地震作用的结构响应。选取15条地震加速度时程，通过重复法构造人工主余震序列并进行IDA分析，得到结构在不同强度的主余震序列作用下的地震易损性曲线。结果表明:主震PGA越大，余震的最大层间位移角越大，结构达到各极限状态的概率越高。对比配置不同钢筋强度的三榀框架的计算结果，可知"等强代换"原则下，相同主余震序列作用时，钢筋强度的提高对结构抗倒塌性能有不利影响，但影响有限。

Fragility analysis of high strength reinforced concrete frame structures subjected to mainshock-aftershock earthquake sequences

In order to study the seismic performance of RC frame structure with high strength reinforcement under the action of main-aftershock，three frames of six-story four-span reinforced concrete structure were designed according to the same design index and the principle of equal strength substitution. The strength grade of longitudinal reinforced bar was HRB400，HRB500 and HRB600，respectively. Finite element modeling was carried out on the OpenSees platform，and the maximum interstorey drift was used as the structural damage index to reflect the structural response to the earthquake. Fifteen seismic acceleration timescales were selected，artificial main-aftershock sequences were constructed by repetition method and IDA analysis was carried out to obtain the seismic vulnerability curve of the structure under the action of main-aftershock sequences of different intensity. The results show that with the increase of PGA，the interstorey under aftershock becomes more obvious，and the structure has a greater probability of reaching each limit state.By comparing the calculation results of three trusses frames with different reinforcement strength，the increase of reinforcement strength has a negative effect on the collapse resistance of the structure under the principle of equal strength substitution and the action of the same main-aftershock sequences， but the effect is limited.