多维性能极限状态平面不规则结构易损性分析
Multidimensional Performance Limit States for Fragility Analyze of Plane Irregular Structure

针对平面不规则框剪结构，在引入最不利输入角度的基础上，提出多维性能极限状态的易损性分析方法。首先,利用Matlab中小波变换系数法，判别地震动的最不利输入方向；然后，采用层间位移和层间扭转角作为性能量化指标并考虑量化指标间的相关性，计算超越概率，从而得到二维性能极限状态下结构的易损性曲线。利用该方法对平面不规则框剪结构进行分析得到结构在正常使用、可以使用、生命安全、防止倒塌4个性能水平下的易损性曲线。结果表明：对于平面不规则结构，地震动输入角度对结构的抗震性能有不可忽略的影响；对平面不规则结构进行易损性分析时，应同时考虑层间位移和层间扭转角双指标的影响，防止高估这类结构的抗震性能。基于多维性能极限状态的易损性分析方法对平面不规则结构抗震性能的评估更为安全、可靠。
Based on the introduction of the critical angle, a new method for multidimensional performance limit states is developed to analyze the structural fragility of plane irregular frame-shear-wall structures. First, the critical angle of seismic wave is determined using the wavelet transform in Matlab. Then, concerning the dependency of the limit states, the probability of exceedance can be calculated by adopting the inter-story drift and inter-story torsion angle as the quantitative indexes. The fragility curves are achieved under two dimensional performance limit states. Using this method to analyze the aforementioned structure, the fragility curves under four performance levels are obtained, which are normal operation, immediate occupancy, life safety, and collapse prevention. The results indicated that the critical angle of seismic wave has a significant impact on the performance of the plane irregular structures. In order to avoid overestimating seismic performance of plane irregular structures, inter-story drift and inter-story torsion angle should be simultaneously considered. Therefore, for plane irregular estimate, the analysis method of fragility under multidimensional performance limit states is more safe and reliable.