基于增量动力分析的高烈度区框架-核心筒结构地震易损性分析

Seismic vulnerability analysis of frame-core wall structure in high seismic zone based on incremental dynamic analysis

基于增量动力分析方法和数理统计,可有效进行结构地震易损性分析。以一个8度区、98m高的框架-核心筒结构为例,采用增量动力分析方法,以结构最大层间位移角为性能参数,进行结构地震易损性分析和抗震性能评估。结果表明,随地震动强度增大,结构损伤程度加重,刚度逐步下降、周期延长,结构层间位移角增大。但因出现的薄弱位置不同,最大层间位移角会出现随地震动强度增大而减小的情况,因此抗震性能评估中需考虑楼层因素。地震易损性分析结果得到,结构在小震、中震和大震作用下处于正常使用、修复后使用和生命安全的概率最高,表明结构能够满足“小震不坏、中震可修、大震不倒”的抗震要求。增量动力分析方法,能够获得结构完整的非线性响应,可从概率角度量化结构抗震性能,并有效反映结构薄弱部位,是结构抗震性能评估的有效手段。

Structure seismic vulnerability analysis can be obtained by the incremental dynamic analysis(IDA) method and mathematical statistics effectively. Seismic vulnerability analysis and seismic performance evaluation of a 98 m height frame-core wall structure located at 8 degree zone were studied through IDA method which took the max story drifts as the performance parameter. The results show that with the earthquake intensity increasing, the structure damage worsened, the literal stiffness decreased, the structure periods prolonged and the story drifts increased. But for the weak floors were different in nonlinear stages, the max story drifts would decrease with the earthquake intensity increasing. Therefore, the floor factors should be considered in structural seismic performance evaluation. The seismic vulnerability analysis results show that the probability of in serviceability state, reparability state and life safety state were the highest under the frequent earthquakes, the design based earthquakes and the rare earthquakes. The structure can meet the requirements of ‘perfect subjected to frequent earthquake, reparable subjected to design based earthquake, no collapse subjected to rare earthquake’. Incremental dynamic elastoplastic analysis which was an effective way to evaluate the structural seismic performance can obtain the complete nonlinear response of structure, quantify the seismic performance of structure from the probabilistic point of view and reflect the structure weak floors.