轴心受压H型截面钢柱火灾行为的试验研究

Experimental Investigation of the Behaviors of Axially Loaded H-Section Steel Column under Fire

本文对4根H型截面钢柱进行了火灾行为的试验研究。全部火灾试验采用自行研制的火灾试验炉,试验结果表明炉子性能稳定,使用方便。试验采用足尺试验形式,柱长3300mm。钢柱轴心受压,其中两个限制轴向变形,另两个不限制轴向变形。柱两端采用单向刀口支座,允许钢柱绕强轴转动。钢柱试验中考虑荷载大小和是否限制轴向变形两个因素。通过试验,得出了钢柱在火灾下的侧向变形和轴向变形随温度变化情况。试验证明:钢柱受火时,轴向变形明显的分为膨胀阶段和压缩阶段。压缩阶段很短,一旦进入压缩阶段,钢柱很快破坏。钢柱受到的外加荷载越大,其极限温度越低。限制轴向变形的钢柱极限温度降低。试验研究为今后钢结构火灾行为研究提供了依据。

Behaviors of four H-section steel columns under fire were investigated in this paper. The tests were performed with the self-developed fire-test furnace which is reliable and convenient. All the columns were full scale with 3300mm length and suffered axial force. Two columns were axially restrained and the other two were freely expansive. Two ends of the columns were supported with knifeedges and permitted to rotate around strong axes. Effects of axial restraint and loading level on behavior of steel columns exposed to fire were investigated. From the test results, the regularities of lateral deflection and axial deformation are presented. The test results show that axial deformation of the steel columns can be divided into two stages： expansive stage and compressive stage. The compressive stage is very short and steel columns quickly happen to destroy. Increasing the loading level causes a drop in the failure temperature of steel columns. Failure temperature of axial restrained columns is lower than that of free expansive columns. The conclusions of this paper provide a basis for further research to explore fire behaviors of steel structures.