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传统的地震倒塌易损性分析中通常只考虑地震动不确定性的影响。在结构临近倒塌时,通常处于高度非线性状态,会出现结构不确定性与地震动不确定性的耦合放大现象。针对这一问题,将平均值一次二阶矩方法(MVFOSM)与逐步增量动力分析(IDA)相结合,提出了一种可以考虑结构不确定性的基于MVFOSM的随机IDA方法。以五层三跨钢筋混凝土框架结构为例,采用基于MVFOSM的随机IDA方法对其进行了地震倒塌易损性分析,并利用“龙卷风图”方法对结构抗地震倒塌能力的灵敏度进行了分析。研究表明:结构不确定性的存在使得结构抗地震倒塌能力的对数标准差增加了70%,因此有必要在地震倒塌易损性分析中考虑结构不确定性的影响。
The traditional seismic collapse vulnerability analysis usually only considers the influence of the earthquake’s uncertainty. Near the collapse of the structure, usually in a highly nonlinear state, there will be coupled with the structural uncertainty and the uncertainty of ground motion amplification phenomenon. To solve this problem, we propose a MVFOSM-based stochastic IDA method which can consider the structural uncertainty by combining the averaging second-order moment method (MVFOSM) with incremental incremental dynamic analysis (IDA). Taking the five - storey three - span RC frame structure as an example, the vulnerability of seismic collapse was analyzed by random IDA method based on MVFOSM and the sensitivity of the structure to earthquake collapse resistance was analyzed by using the method of “Tornado diagram” . The results show that the existence of structural uncertainty increases the logarithmic standard deviation of seismic collapse resistance by 70%, so it is necessary to consider the influence of structural uncertainty in the seismic collapse vulnerability analysis.