摘要
为研究受约束钢柱在火灾下的失效全过程响应,以及静力分析方法是否依然适用于临界温度之后的响应分析,建立了柱端受轴向和转动约束的钢柱火灾下简化分析模型,考虑两种不同的工况,分别采用静力和动力分析方法对受火钢柱进行了失效全过程分析。结果显示,根据约束刚度大小以及承受荷载大小的不同,受约束钢柱在火灾下的屈曲后响应可能是拟静力的,也可能伴随显著的动力效应。钢柱温度达到临界温度以前,静力分析、拟静力分析与动力分析结果基本一致。钢柱达到临界温度后的响应,若柱后屈曲响应为拟静力过程,则静力分析与动力分析结果基本一致,若柱后屈曲响应存在明显的动力效应,则静力分析会不收敛,拟静力分析得到的最大柱顶竖向位移会小于动力分析的结果。因此对于钢柱后屈曲响应,静力分析、拟静力分析可能导致偏于不安全的抗火设计。
To study the whole failure process of restrained steel columns under fire and the applicability of static analysis in post buckling analysis under fire, this paper develops a simplified model of restrained columns under fire considering two cases and analyzes the columns using stat- ic and dynamic method respectively. The results show that the column may buckle gradually or suddenly depending on the condition of restraint stiffness and load ratio. And for the behaviour of columns below critical temperature, the differences of results among static analysis, quasi-static analysis and explicit dynamic analysis are negligible. For the post buckling behaviour, if the buckling process is gradual, the results of static analysis and explicit dynamic analysis methods are almost the same; if the buckling process is dynamic, static analysis may be terminated with convergence difficulties and quasi-static analysis may underestimate the largest vertical displacement at column top. Therefore, for the fire design which needs to consider the post buckling behaviour of columns, static analysis and quasi-static analysis may lead to unsafe design.
出处
《防灾减灾工程学报》
CSCD
北大核心
2016年第3期405-408,共4页
Journal of Disaster Prevention and Mitigation Engineering
基金
国家自然科学基金重大国际合作研究项目(51120185001)资助
关键词
钢柱
火灾
动力效应
后屈曲
分析方法
steel column
fire
dynamic effect
post-buckling
analysis method
