开孔薄壁钢梁-轻骨料混凝土组合楼板火灾后受力性能研究

针对一种由冷弯卷边H型开孔薄壁钢梁和轻骨料混凝土预制板装配而成的新型轻质组合楼板, 对一组两端简支的组合楼板试件开展了烃类火灾作用后的力学性能试验研究. 结果表明, 承担2kN?m-2均布荷载的组合楼板试件在遭受600℃烃类火灾作用后, 仍具有较高的承载能力和整体刚度. 在4kN?m-2的均布荷载作用下, 火灾后损伤最严重的组合楼板试件的跨中挠度仍小于L/400, 且未见混凝土的进一步开裂. 试验结果表明, 薄壁钢梁腹板开孔形式及抗剪键的数量对火灾后组合楼板的整体刚度和受力性能有明显影响, 从提高组合楼板整体刚度的角度考虑, 对主钢梁腹板的开孔宜首选孔径大、数量少的分布形态, 同时适当增加抗剪键数量.

Study of post-fire mechanical property of composite slabs of lightweight concrete and thin-walled steel beams with openings in web member

This paper addresses a new type of composite slab assembled with precast lightweight aggregate concrete panels and thin-walled H-steel beam with openings in web member. Experimental study is conducted on the post-fire mechanical performance of the composite slabs simply supported at two ends. The results show that the composite slabs under uniform load with value of 2kN?m-2 and after exposure to hydrocarbon fire with maximum temperature of 600℃ remain higher bearing capacity and post-fire integral rigidity. It is found that the composite slab which suffers the most serious damage in fire still keeps the deflection less than L/400 under uniform load of 4 kN?m-2, and there is no more crack found in concrete of the slab specimen. It can be concluded based on the test results that the form of openings in web member of the thin-walled steel beam of the composite slabs and the number of the shear connector have obvious effect on the post-fire integral rigidity and mechanical property of the composite slabs. Also suggested is that the form of the openings with larger diameter and smaller number and properly increasing the shear connector’s number should be used with first priority for enhancing integral stiffness of the composite slabs.