火灾下约束钢柱临界温度的参数分析

Parametric Studies on Critical Temperature of Restrained Steel Column in a Fire

利用经实验验证过的ABAQUS有限元模型对轴力和弯矩共同作用下的约束钢柱进行了参数分析。以钢柱的屈曲温度和临界温度作为主要的评价指标,主要考虑了轴力荷载比、弯矩荷载比、轴向约束刚度比、转动约束刚度比、长细比和钢柱端部弯矩比等参数的影响,并且对不同参数之间的耦合性进行了分析。参数分析结果表明,轴向约束刚度的增大将会明显降低约束钢柱的屈曲温度,但是对其临界温度的影响相对较小;端部弯矩比对钢柱的临界温度影响很小;当钢柱的轴力荷载比和弯矩荷载比较小、轴向约束刚度比和长细比较大时,考虑屈曲后性能可以显著提高钢柱的抗火能力。

This paper investigates the critical temperature of a restrained steel column in a fire by using the ABAQUS finite element method model.Results are presented by the buckling temperatures and critical temperatures of steel columns.The influence of axial load,bending moment,axial restraint,rotational restraint, slenderness and end moment ratio is considered in the parametric study.The coupling between parameters has also been analyzed.Results of parametric study show that：①The axial restraint will reduce the buckling temperature of the restrained steel column significantly,but the critical temperature is scarcely affected by the restraint;②The end moment ratio has a very small influence on the critical temperature of steel columns;③The performance of steel column in fire will be much better if the post-buckling behavior is considered,when the axial load ratio and bending moment ratio of the column are small and the slenderness of the column is large.