单跨组合梁火灾变形性能研究

Deformation investigation of single-span composite beam subjected to fire

为研究整体结构中组合梁在火灾中的的变形性能,采用试验方法对2个组合梁进行研究,考虑组合梁在整体结构中所处位置的不同2种工况.试验中量测了炉温、组合梁沿截面高度不同测点的温度、组合梁的竖向变形.结果表明:在火灾试验过程中,组合梁同一截面存在较大的温度梯度,产生温度应力,而相邻构件的约束使得组合梁不能自由变形,以致组合梁的竖向变形在升温阶段就开始恢复,最后产生向上的变形;组合梁在整体结构中所处位置不同,其火灾变形性能也不同.整体结构中裸露的组合梁表现出很好的抗火性能.

To study the deformation performance of composite beam in whole structure subjected to fire,we have carried out two fire experiments of composite beams considering different working conditions in whole structure.The furnace temperature and the temperature of different points in the same section were measured,as well as the vertical deformations at different sections were detected during the experiment.The results showed that：in the fire tests,the composite beams across the same section had a big temperature gradient,which generated thermal stress.However the composite beams couldn＇t deform freely because of adjacent components,the vertical deformation of composite beam began to recover in the warming phase and was up-ward finally;The fire behaviors of different composite beams in whole structure was different.Exposed com-posite beam in whole structure shows the good fire resistance.