轻骨料混凝土组合楼板的火灾响应及火灾后性能研究

对一组具有不同参数的轻骨料混凝土组合楼板开展了火灾响应及火灾后承载力试验研究。试验用轻骨料为一种烧制陶粒,楼板的制作主要考虑了板厚的变化及栓钉的设置。对承载条件下的4块简支陶粒混凝土组合楼盖进行了火灾行为试验,分别得到了其火灾响应温度及位移响应。为了考察该类组合楼盖火灾后的受力性能,进一步进行了火灾后的承载力试验研究,并与一块未受火灾作用的楼盖进行了对比试验。结果表明,增加楼板厚度不仅能提高轻骨料组合楼板的抗火性能,也能提高其在火灾后的承载力。但是,在楼板内部设置焊接栓钉会减弱组合楼板的抗火性能,降低组合楼板在火灾后的承载力;压型钢板-陶粒混凝土组合楼盖受火后整体刚度虽然有明显下降,但仍具有较高的承载力,且塑性性能良好;陶粒混凝土组合楼盖的热响应温度沿楼板板厚方向的变化呈明显的非线性,但可近似为两个线性变化段。

Study on fire response and post-fire behavior of lightweight aggregate concrete composite floor

This paper performed an experimental study on fire response and post-fire bearing capacity of a set of lightweight aggregate concrete composite floor.The aggregate used in the test is a type of burned ceramsite,and the composite floors are made considering variation of thickness and arrangement of shear studs.First,experiments of fire behavior of four simply supported composite floors under static load were conducted to obtain the response temperatures and displacements of the floors under fire.Then,to investigate the post-fire mechanical performance of the floors,experimental study of the residual bearing capacity of the composite floors after exposure to fire was conducted,to compare with the mechanical performance of a floor not subjected to fire,which has the same dimension and construction with one of the floors subjected to fire.Experimental study showed that,increase of thickness of the composite floor is helpful to strengthen the fire-resistant behavior and the post-fire bearing capacity of the composite floor.However the welding studs set in the floor can weaken the fire-resistant capacity and the post-fire bearing capacity of the composite floor;the composite floor after exposure to fire still has high post-fire bearing capacity and good plasticity,although its stiffness obviously decreased.The variation of response temperature of the floor is nonlinear along floor thickness,but the curve can be simplified as two line segments.