铰接叠合板组合梁抗火性能试验研究

为研究铰接叠合板组合梁的抗火性能，对2个铰接足尺叠合板组合梁进行了恒载升温试验研究和数值模拟。通过试验得到了叠合板组合梁的温度分布、位移变化和破坏模式。研究结果表明：叠合板的温度分布沿板厚方向逐渐降低，距受火面40mm以下区域受火影响最为明显。叠合板与钢梁之间存在温度梯度，叠合板对钢梁上翼缘变形有约束；叠合板板顶裂缝主要沿中轴线方向开展，从两端向中间延伸，叠合板中预制底板与后浇层的叠合界面没有开裂，二者在火灾下仍能协同工作；冷却后两试件的变形恢复比例相近，表明叠合板后浇层厚度对变形恢复能力的影响小；叠合板后浇层厚度对叠合板组合梁的抗火性能影响较小。有限元模拟结果与试验结果吻合较好，利用建立的有限元模型可以对叠合板组合梁的抗火性能进行后续参数分析等研究。

Experimental study on fire resistance of laminated-slab composite beams under hinged connection

To investigate the fire resistance of laminated-slab composite beams under hinged connection, the experimental study and numerical simulation of two laminated-slab composite beams were carried out subjected to constant load and fire. The temperature distributions, displacement changes and failure modes were obtained through the experiment. It is found the temperature of the laminated slabs gradually decreases along the direction of thickness of slab, and the regions below 40mm are influenced more obviously. There is a temperature gradient between the laminated-slab and the steel beam, and the laminated-slab restricts the deformation of the upper flange of the steel beam. The cracks at top surface of laminated slab extend along the direction of central axis, and extend from both ends to the mid-span. There is no crack at the surface between prefabricated slab and post-poured layer, so the laminated slab can still work together. After cooling, the recovery ratios of deformation of two specimens are similar, which shows that the thickness of post-poured layer has little effect on the deformation recovery capacities. And the thickness of post-poured layer has little influence on fire resistance of laminated-slab composite beams. The numerical simulation results and test results are in good agreement, so the model can be utilized for subsequent parametric analysis about fire resistance of laminated-slab composite beams.