Nataf变换的桥梁系统多维地震易损性分析方法

在多维性能极限状态理论框架下,考虑桥梁各构件地震响应参数相关性,引入Nataf变换,提出了改进的桥梁系统多维地震易损性分析方法;以一座三跨V撑连续梁桥为例,利用OpenSees软件建立桥梁系统非线性动力分析模型,从美国太平洋地震研究中心强震数据库中选取20条地震波进行增量动力分析,并获得桥梁结构在地震作用下的最大响应样...

Multi-dimensional seismic fragility analysis method of bridge system based on Nataf transformation

In the framework of multi-dimensional performance limit state theory, the correlation of seismic response parameters of bridge components was considered, and an improved multi-dimensional seismic fragility analysis method of bridge system was proposed by introducing Nataf transformation. Taking a three-span V-shaped continuous girder bridge as an example, the nonlinear dynamic analysis model of the bridge system was established by using OpenSees software, 20 seismic waves were selected from the strong earthquake database of Pacific Seismic Research Center for the incremental dynamic analysis, and the maximum response samples of the bridge structure under earthquake were obtained. The maximum likelihood estimation method was used to obtain the statistical parameters of the bridge component's seismic demand probability model. Combined with the defined bridge component damage index, the seismic fragility of the example bridge multi-dimensional system was analyzed by using the proposed method. Analysis results show that on the basis of considering the correlation between the seismic response parameters of the components and the performance limit states, the proposed method can calculate the fragility of the bridge system without relying on the joint probability density function between the seismic response parameters of the components. When constructing the multi-dimensional limit state equation, the influence deviation of the bridge component failure mode ranking on the multi-dimensional seismic fragility of the bridge system is less than 3%, so the component failure mode ranking has little influence on the fragility analysis result. In any damage state, with the increase of the correlation coefficient between the ground peak acceleration and the limit state, the ratios of the failure probability of the bridge system and the transition pier under the action of earthquake gradually decrease and approach 1, the correlation between the performance limit states of different bridge components becomes weaker, and the area of the system failure domain becomes smaller, resulting in that the failure probability of the bridge system reduces, and the multi-dimensional fragility of the bridge system is closer to the evaluation result when the performance indexes are independent of each other. When the multi-dimensional performance indicators are used, their correlation cannot be ignored, otherwise it will lead to the overestimation of the seismic performance of the bridge structure. 4 tabs, 6 figs, 30 refs.