H型钢梁(端板连接)火灾行为的试验研究

为研究钢结构抗火性能,对4根端板连接H型钢梁进行火灾行为的试验研究.全部火灾试验在自行研制的火灾试验炉上进行,采用足尺试验形式,考虑跨度、荷载大小两个主要因素.钢梁跨度分别为4 200,3 600 mm,荷载比率分别为0.48,0.78.得出钢梁的温度场分布、变形情况及端板连接、轴向约束对钢梁的影响.结果表明:H型钢梁在火灾作用下发生局部屈曲和弯扭屈曲现象;端板连接、轴向约束对H型钢梁的火灾行为影响明显;钢梁进入大变形阶段后,轴向约束压力变为轴向约束拉力,轴向拉力有阻止钢梁自身进一步变形的作用,即发生了悬链线作用.

Experimental investigation of behaviour of H-section steel beams (end-plate connection) under fire

The behaviour of four H-section steel beams(end-plate connection) under fire is investigated.The whole test is carried out using the self-made fire-test furnace.All the beams are full scale with 4 200 mm and 3 600 mm lengths.Steel beams are tested at two load ratios of 0.48 and 0.78.Through experiment,the distpibution of temperature field and deformation are obtained.The effects of end-plate connection and axial restraint on the behaviour of steel beams are also attained.The results of experiment reveal that local buckling and lateral torsional buckling take place in H-section steel beams under fire.The behaviour of H-section steel beams under fire is influenced by end-plate connection and axial restraint.When the beam undergoes a large deformation,compression force then quickly changes into tension force which supports the beam and reduces further deformation,that is to say,catenary action takes place.