两层两跨组合钢框架抗火性能的试验研究

利用自行研制的火灾试验炉,对3榀两层两跨组合钢框架在不同火灾工况下的性能进行了试验研究,火灾工况包括:单室受火、同跨受火和底层受火三种工况,试验时,梁、板、柱同时受火,节点不受火.试验中量测了各种工况下的炉温,框架梁、柱及混凝土楼板中的温度分布及框架水平和竖向位移.结果表明:钢柱四面受火时,钢柱翼缘、腹板的温度相差很小;而单面受火时则相差较大;对于钢梁,除了与混凝土接触的上翼缘外,其余H型钢梁的裸露部分温度基本一致;混凝土内部的温升一般滞后于钢梁,钢筋混凝土板对钢梁有约束作用,升温时混凝土限制钢梁的膨胀,降温时则限制钢梁的收缩,致使钢筋混凝土板中出现很多裂缝;组合钢框架在降温时因为收缩,导致节点等处出现不同程度的破坏,并产生很大的残余变形;钢框架未受火部分对受火部分约束很大, 导致受火跨边柱与中柱的变形不对称, 同样也产生了内力重分布;组合梁的抗火性能明显优于钢柱,工程中应对钢柱和节点实施保护.

Experimental Study on Performance of 2-Storey and 2-Bay Composite Steel Frames Subjected to Fire

Using the special fire furnace and experimental set-up designed for 2-bay and 2-storey composite steel frames,the performance of 2 full scale 2-bay and 2-storey composite steel frames in the same span fire were studied.During tests,the beam-column connections were protected.The temperature distributions along steel beam,column profile and across reinforced concrete slab were measured;meanwhile the displacements at middle and top of columns were recorded also during experiments.It is found that the temperatu...