高温下两铰圆弧钢拱平面内稳定临界荷载分析

The critical load analysis of the big curvature circular double-hinged steel arch stability in plane under high temperature of fire

针对目前钢拱结构在高温下的非线弹性反应研究方面存在的不足,尤其是其在高温下的稳定性变化问题,研究了火灾高温下大曲率两铰圆弧钢拱的平面内稳定及临界荷载的变化.给出了高温下两铰圆弧钢拱的平面内稳定临界荷载的计算表达式,分析了其随火灾温度的变化规律,结果表明:火灾高温下钢拱结构的内部温度、材料的力学性能改变会引起结构内力和变形的增大,从而对其稳定性和临界荷载的变化都产生显著的影响,因此在进行火灾高温下钢拱结构的非线性反应分析时,应综合考虑结构内部不同因素的变化对结构整体力学性能的影响.

Aiming at the shortage of nonlinear elastic response analysis of the steel arch under fire condition, espe- cially the change of stability in high temperature, the changes of stability in plane and critical load of the big curva- ture circular double-hinged steel arch exposed to fire were investigated. The expressions of critical load are proposed and their variation trends along with the change of high temperature of fire were also analyzed. The results show that the structure internal force and deformation increase due to the variations of internal temperature and mechanical properties of materials. Accordingly, the stability and the critical load were significantly affected. Therefore, the in- fluence of different internal factors on whole mechanical properties of the structure should be considered when the nonlinear responses of the steel arch under fire condition are analyzed.