结构需求概率危险性分析中强震记录选取研究

The research of strong ground-motion records selection for estimating the structural demand hazard curve

目前结构性态地震工程中易损性曲线传统计算流程对强震记录选取不够重视,鲜有对目标场址地震概率危险性的考虑,因而以同时考虑地震概率危险性和结构自振周期特性的条件均值谱作为记录选取依据,将结果应用到IDA方法和条带法中,并与地震事件随机散布的传统云图法进行对比。以某八层平面框架作为算例,将云图法与IDA方法以及条带法在四种极限状态下的结构需求易损性曲线以及结构需求概率危险性曲线进行对比分析。其中,随机选取两组地震事件(M,R)分布范围相仿的强震记录进行云图法计算,二者结果由于不可控的地震动不确定性而存在显著差异,但IDA方法与条带法由于采用条件均值谱对地震动进行了控制,彼此结果基本一致,更符合实际工程场址的危险性需求,同时为后期不同区域的结构性态分析损失评估提供了依据。

The ground-motion selection is neglected on the traditional fragility demand curve of structural seismic engineering, and the seismic hazard is rarely considered. The conditional mean spectrum(CMS) ground-motion selection method was introduced into the IDA method and stripe method to solve the problem, and compared with the traditional cloud method with disperse ground-motion records. Conditional mean spectrum was constructed based on the China seismic disaggregation result and attenuation relationship. The fragility demand curves and the demand hazard curves of one eight-stories 2D structure were computed using the three different methods. With the two different ground-motion records selection as the input of the traditional cloud method, the two group results are significant variation. Considering the merit of CMS selection in IDA method and stripe method, the results are coherence and could be applied in the subsequent loss estimation study in performance based earthquake engineering.