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由冷弯薄壁钢梁和陶粒混凝土预制板组成的装配式组合楼板具有轻质、高强和施工方便等优点。为研究该类组合楼板的抗火性能及高温后的受力性能,对6块遭受温度为700℃、持续90 min烃类火灾升温作用的简支组合楼板试件进行受火后受力性能试验研究。结果表明:当施加的等效均布荷载达到2 kN/m~2时,受火作用后的组合楼板试件最大挠度小于跨度的1/400,且在加载过程中薄壁钢梁虽已明显扭曲、混凝土板多处开裂,但组合楼板试件未出现整体坍落现象;以普通栓钉为抗剪键的受火后组合楼板试件,其极限荷载比薄壁钢抗剪键组合楼板试件的提高14.2%;当用钢量相同时,主梁数量较多的组合楼板试件采用U形钢筋作为拉结件,其火灾后极限荷载比采用钢条拉结件的组合楼板试件的增加33%,且整体刚度也有所提高;该类组合楼板在受火后仍具有较高承载能力和整体刚度,且抗剪键类型、预制板之间设置的拉结件以及拉结件与抗剪键的连接方式均对其受火后的受力性能有较大的影响。引入组合效应系数可以较好地反映受火后组合楼板试件的组合效应及内部损伤程度。
Assembled floor slab composed of cold-formed thin-walled steel beam and ceramsite concrete prefabricated slab has the advantages of light weight, high strength and convenient construction. In order to study the fire resistance performance of the composite floor slab and the mechanical properties after high temperature, six kinds of simply supported composite slab specimens subjected to the temperature rise of 700 ℃ for 90 min were subjected to the fire performance test the study. The results show that when the equivalent uniform load is applied to 2 kN / m ~ 2, the maximum deflection of the composite floor slab under fire is less than 1/400 of the span, and the thin-walled steel beam has been obviously distorted during the loading process. Concrete slabs were cracked in many places, but the overall floor slab specimens did not appear the whole slump phenomenon. The ultimate load of fire-damaged composite floor slabs with common studs as shear bond increased by 14.2% %; When the same amount of steel used, the number of the main girder more composite floor specimens using U-shaped steel as the pull-knot, the ultimate load after fire than the use of steel-pull composite floor samples increased by 33% And the overall rigidity has also been improved; such composite floor after the fire still has a high carrying capacity and overall rigidity, and the type of anti-shear, the pre-set between the plate and the connection between the pull fastener and shear bond Methods are subject to the fire after the stress performance have a greater impact. The combination effect coefficient can reflect the combination effect and the degree of internal damage of the composite floor slab under fire well.