火灾荷载作用下轴压钢构件临界应力分析

以轴压钢构件为研究对象,探讨火灾场荷载作用下结构钢材料的弹性模量、抗弯刚度、屈服强度的变化规律,且在这些材料基本参数改变的前提下分析了轴压钢构件的临界应力和临界力,最后进行实例数值分析,得出轴压钢构件在火灾高温条件下钢结构材料的弹性模量、抗弯刚度和屈服强度都急剧下降,降幅在火灾持续时间2h左右达50%以上,轴压钢构件的临界应力也快速下降,使钢构件的承载能力下降很快,导致结构破坏。因此,在钢结构设计中,必须考虑火灾高温对轴压钢构件的临界应力和临界力降低的影响。

DYNAMIC RESPONSE ANALYSIS OF SIMPLY SUPPORTED STEEL BEAM UNDER NATURAL FIRE FIELD

In this paper,the axial compression steel members as the object,and the change law of elastic modulus,bending rigidity and yield strength of structural steel under the action of fire field was discussed in this paper.The axial critical stress and critical pressure of steel components were analyzed on the premise of changing basic parameters of these materials,finally,a numerical example is carried out to show that the elastic modulus,flexural rigidity and yield strength of the steel members under the fire and high temperature are sharply decreased,the decrease in the fire duration of 2 hours is over 50％,the critical axial compression steel stress also decreased rapidly,so that the bearing capacity of steel decreased rapidly which led to structural failure.Therefore,in the design of steel structure,the critical stress of the steel member under axial compression and the reduction of the critical force must be considered.