基于性能的门式刚架抗火性能研究

PERFORMANCE-BASED EVALUATION ON THE FIRE-RESISTANT PERFORMANCE OF PORTAL FRAME STRUCTURE

基于性能化抗火设计思想,利用场模拟软件FDS(Fire Dynamics Simulator)对门式刚架钢结构厂房各种可能的火灾场景进行仿真分析,获得火灾升降温全过程的时间-温度曲线。在此基础上,运用ANSYS建立有初始缺陷的门式刚架有限元模型对其火灾全过程的力学性能进行直接分析。结果表明,当发生火源功率达到25 MW的严重火灾时,对于柱脚形式为铰接的门式刚架,结构很快发生侧移破坏,需要对整榀刚架进行防火保护,但柱脚如果采取固接形式,则只需对钢柱进行防火保护。当仅发生火源功率不超过5 MW的一般火灾时,只对钢柱进行防火保护即可。

Based on the concept of performance-based design,various fire scenarios of single-story buildings formed by portal frames were simulated by FDS（ Fire Dynamics Simulator） and the temperature-time curves of the hot smoke were obtained. Then the portal frames subjected to simulated fire were carried out by direct analysis with consideration of initial imperfections by using ANSYS program. The results showed that the portal frame with pinned supports would collapse in a sway mode and as a result the whole structure need fire protection for 25 MW fire. However,only the columns need to be protected when the supports of the portal frame were assumed as fixed. In the case of 5 MW fire,only the columns need fire protection.