薄壁槽钢柱的抗火计算方法及参数分析

基于Rankine公式，提出了一种可用于计算热轧薄壁槽钢柱抗火极限的方法，采用有限元软件MSC．MARC．Mentat对模型进行非线性有限元分析，给出模型网格划分及其失效后的变形图。对比有限元分析结果与理论解，吻合较好。并针对薄壁槽钢柱的长细比、扭转刚度参数及截面的宽高比，对其抗火性能的影响进行参数分析。结果表明：长细比是影响柱子抗火能力的最重要的因素，长细比越大，极限抗火承载力越低；弹性弯扭屈曲向弯曲屈曲转化的临界长细比不随温度的改变而改变；对于薄壁槽钢柱而言，在截面面积一定或近似的情况下，截面宽高比越大，扭转刚度参数K越小，柱子在火灾下的极限承载力越好。

Fire resistance of thin-walled steel channel column and parameter analysis

This paper presents a new design method for thin-wall hot-rolled channel columns in fire condition using Rankine formula.The finite element method(FEM) analysis is to validate the new proposed method.The analytical results are reasonably accurate,as comparing to those of finite element simulation.Some effects of parameters on fire resistance are investigated.The results show that the slenderness ratio is the main factor,which affects the fire resistance of thin-walled channel column,its crease can diminishes the load bearing capacity in fire condition;the critical slenderness ratio,at which the elastic flexural-torsional buckling is transferred to elastic flexural buckling can not be changed by elevated temperature;with almost the same cross-section areas,the hot-rolled thin-walled channel section with wide flange and shallow web can get small torsional parameter K but high load ratio and great fire resistant capacity.1 tab,14 figs,8 refs.