震后火作用下多层钢框架基于火灾荷载密度的易损性分析

Vulnerability Analysis of Multi Story Steel Frames under Post-Earthquake Fire based on Fire Load Density

与地震易损性相比,结构震后火的易损性研究尚未深入。以三层三跨平面钢框架为研究对象,采用ABAQUS进行建模,选取火灾荷载密度作为火灾强度指标,同时将耐火极限作为破坏状态指标,采取拉丁超立方法生成了50个结构样本,对钢框架进行震后火作用下耐火极限分析和易损性分析,并给出了不同损伤程度的四种破坏状态。研究结果表明:震后火作用下钢框架失效概率随火灾荷载密度的升高而增加;当火灾荷载密度达到最大值时,大震下钢框架发生轻微破坏、中等破坏和严重破坏的概率较高,出现倒塌破坏的概率相对较低;对比三水准地震设防烈度下火灾易损性曲线,随着地震烈度的升高,钢框架发生严重破坏和倒塌破坏的概率也随之增大。

Compared with seismic vulnerability,the research on post-earthquake fire vulnerability of structures has not been in-depth studied. Taking a three-story three-span plane steel frame as the research object,ABAQUS is used for modeling,the fire load density is selected as the fire strength index,and the fire resistance limit is taken as the failure state index. Fifty structure samples are generated by Latin hyper method to analyze the fire resistance limit and vulnerability of the steel frame under post-earthquake fire. Four failure states with different damage degrees are given. The results show that the failure probability of steel frames under post-earthquake fire increases with the increase of fire load density;When the fire load density reaches the maximum,the probability of slight failure,medium failure and serious failure of steel frame under large earthquake is high,and the probability of collapse failure is relatively low;Compared with the fire vulnerability curve under three-level seismic fortification intensity,with the increase of seismic intensity,the probability of serious damage and collapse of steel frame also increases.