地震动谱匹配对多层RC框架结构地震易损性分析结果的影响

Influence of Spectrum-matched Ground Motion on Seismic Fragility Analysis Results of Multi-storey RC Frame Structures

合理选择地震动记录是影响结构增量动力分析和易损性分析结果可靠度的重要因素之一。首先选择15条地震动记录分别运用谱匹配方法进行不同周期范围的调整,然后输入谱匹配前后6组地震动记录,对一个5层和11层钢筋混凝土(RC)框架结构进行增量动力分析,并利用增量动力分析结果,得到基于最大层间位移角的不同损伤状态结构地震易损性曲线,以及不同损伤状态50%超越概率对应的最大残余层间位移角统计值。分析结果表明,运用谱匹配方法,结构地震易损性离散性明显减小;随着结构退化程度的增大,与结构基本周期对应的反应谱值相比,等效周期对应的反应谱值对结构非线性地震响应结果的影响更加显著。

A reasonable selection of input ground motion records was an important issue for the reliable incremental dynamic analysis(IDA)and seismic fragility analysis results of the structure.First,spectral matching was used to modify 15 ground motion records in different period ranges.Then,IDA was conducted on a 5-storey and a 11-storey reinforced concrete(RC)frame under the aforementioned 6 sets of ground motion records.Using results of IDA,the seismic fragility curves corresponding to different damage states were obtained based on the maximum inter-story drift ratio,the statistical values of the maximum residual interstory drift ratio corresponding to the 50%exceeding probability with different damage states were proposed.Analytical results showed that by using spectral matching,the dispersion of seismic fragility of structure was significantly reduced.When structure degradation increased,spectral acceleration value corresponding to the equivalent period posed more obvious influence to non-liner seismic response compared to spectral acceleration value corresponding to the fundamental period of the structure.