多类型地震动作用下高层结构的易损性分析

以低频成分为主的长周期地震动容易引起中、长周期结构的破坏,针对这类特殊的地震动,现行抗震规范没有相应的条文,且有关单独考虑长周期地震动作用下结构动力响应的研究成果很少。以一个30层框架剪力墙高层结构为例,利用Perform-3D三维有限元软件进行建模,选取10条远场长周期地震动、10条近场长周期地震动以及10条普通地震动,将最大层间位移角作为工程需求参数,S_a(T₁,5%)作为地震强度指标。基于增量动力分析方法对该结构进行动力时程分析,并定义了4个结构性能水平,然后统计不同地震强度下的结构需求,获取地震易损性曲线,最终对比评价了三类地震动作用下结构的易损性。

Seismic Fragility Analysis for High-rise Structures under Multi-type Ground Motions

The long-period ground motion, which is mainly composed of low-frequency components, can easily cause the damage of medium and long-period structures. For this kind of special ground motion, the current seismic standard does not have corresponding provisions, and there is few studies on the dynamic response of high--rise structure under long-period two-way horizontal ground motions. In this paper, the dynamic time-history analysis of a 30-story frame shear wall high-rise structure is carried out by using the Perform-3D finite element software. 10 far-field long-period ground motions, 10 near-field long-period ground motions, and 10 ordinary ground motions are selected. Meanwhile, the maximum drift is taken as the engineering demand parameter and S_a(T₁, 5%) as the seismic intensity index, and four structural performance levels are defined. Based on the incremental dynamic analysis (IDA) method, the structural responses under different seismic intensities as well as the seismic fragility curves are obtained. Finally, the fragility of the three types of ground motion is evaluated and compared.