基于增量动力分析法的大跨度空间管桁架结构地震易损性分析

SEISMIC FRAGILITY ANALYSIS OF LARGE-SPAN SPATIAL PIPE-TRUSS BASED ON IDA METHOD

增量动力分析法(IDA)是对结构进行抗震评估的一种有效方法。采用挠跨比作为结构性能参数、地面峰值加速度作为地震动强度参数,选取10条地震波,以某实际大跨度空间管桁架结构为研究对象,对其进行增量动力分析。同时,从概率分析的角度,得出结构地震易损性曲线。结果表明:该结构在8度三水准地震作用下达到三种极限状态的概率较小;该结构在8度罕遇地震作用下倒塌概率仅为0.93%,承载能力较高,但延性较低;增量动力分析方法和地震易损性分析相结合可以有效地评估大跨度空间管桁架结构的抗震能力。

Incremental dynamic analysis（ IDA） is an effective method for evaluation of seismic performance of building structures. IDA was used for a large-span spatial pipe-truss,with the ratio of deflection to span being the structure performance parameters and the peak ground acceleration（ PGA） being ground motion intensity measure.Based on the incremental dynamic analysis,the structural fragility curves were achieved in the perspective of probability. The result showed that the probabilities that the pipe truss reaching the three limit states under the three levels of 8-degree earthquake were very low. The pipe truss has a high capacity and can resist 8-degree rare earthquake,but with low ductility. IDA combined with seismic fragility analysis could effectively assess the seismic performance of large-span spatial pipe-truss.