地震作用下基础隔震框剪结构竖向连续倒塌可靠度分析

RELIABILITY ANALYSIS OF THE VERTICAL PROGRESSIVE COLLAPSE OF BASE-ISOLATED FRAME-WALL STRUCTURES UNDER EARTHQUAKES

在引入隔震支座地震损伤模型的基础上,运用整体可靠度理论对基础隔震框剪结构进行竖向连续倒塌可靠度分析。首先,利用隔震支座的地震损伤模型,得到罕遇地震作用下最易失效的隔震支座;然后,在考虑损伤结构不确定性参数的基础上,利用竖向随机动力增量分析(IDA)方法,得到损伤结构竖向连续倒塌荷载系数;以荷载系数为整体性能指标,进行易损性分析;利用基于最大熵原理的二次四阶矩法,计算损伤结构发生倒塌的概率,最后,以一基础隔震框剪结构为例,利用该方法计算损伤结构竖向连续倒塌的可靠度指标及失效概率。研究表明,该方法可直观地得到结构抗竖向连续倒塌的能力,为评估结构在地震作用下产生损伤提供量化依据。

Based on the introduction of a seismic damage model of isolators, a reliability analysis of base-isolated frame-wall structures was conducted using the global reliability method. First, the most probable isolators to fail under strong motions were identified by the seismic damage model of isolators. Considering the basic random variables of damaged structures, progressive collapse load factors were then obtained using the random vertical incremental dynamic analysis method. As a global performance parameter, the load factor was adopted in the performance-based seismic fragility analysis. Probability and reliability indices of progressive collapse were determined using the second-order fourth-moment method. On the basis of this method, the probability and reliability indices of vertical progressive collapse were obtained. By using this method, the performance of progressive collapse resistance and structural seismic damage can be acquired.