框架组合梁抗火性能试验

Experimental study on behavior of frame composite steel beams in fire

为研究框架组合梁在火灾时的结构行为,利用自行研制的火灾加温试验炉及相关测试装置,对2种不同钢筋混凝土与钢梁连接方式共4根框架组合梁在不同的火灾工况下的抗火性能进行了试验研究,火灾工况包括:组合梁、柱同时受火而节点不受火和只有组合梁受火而柱、节点不受火2种.试验中量测了各种工况的炉温,H型钢梁的翼缘、腹板及钢筋混凝土楼板的温度分布和组合梁的挠度随时间的变化.结果表明:钢梁的裸钢部分温度相差很小,而埋入混凝土中的钢的温度比裸钢的低,混凝土板的截面温度差别较大;2种连接方式的组合梁的最大挠度基本相同,破坏形式也很相似,但连接方式2中的混凝土的约束作用要好于连接方式1.在工程中应对框架柱进行防火保护,而框架组合梁可适当放宽要求,对跨度不大的工程可优先使用连接方式2的形式.

To study the structural behavior of frame composite beams in fire, the special fire furnace and experimental set - ups were designed for composite beams of frame. The behaviors of 4 composite beams with different connections in 2 types of fire conditions were studied. The temperature distributions along composite beam sections and across reinforced concrete slab sections were measured; the displacements at middle of composite beams were also recorded during tests. Results indicate that the steel temperatures outside the concrete slab are almost equal, but the steel temperatures inside the concrete are different. Large temperature differences exist across reinforced concrete slab section. The of the temperature steel increases and decreases more quickly than that of the concrete. The deflections of composite beams with different connections are almost equal, and the failure mechanisms of them are also similar. The study shows that the steel columns of frames should be protected in fire; for frame composite beams, protect is not necessary in some conditions.