现浇组合梁抗火性能试验研究与数值模拟

Experimental study and numerical simulation on fire-resistance performance of cast-in-place composite beams

为了对刚接约束下现浇组合梁的抗火性能进行研究,现对刚接约束下的现浇组合梁进行了恒载升温试验研究和数值模拟。在试验过程中,对试验现象进行了详细的观察记录,对现浇组合梁的温度分布和位移变化进行了测量。通过分析试验数据发现,现浇板的温度分布沿板厚方向逐渐降低,板底温度最高,40mm以下区域受火影响最为明显。现浇板会延缓钢梁上翼缘温度的升高,由于温度梯度的影响,现浇板会约束钢梁的变形;现浇板由于温度应力和荷载弯矩的影响,在板顶沿中轴线方向出现贯穿板面的裂缝,冷却后现浇组合梁有较强的变形恢复能力。刚接约束下现浇组合梁的模拟结果与试验结果符合较好,验证了数值模拟的正确性与可行性。

In order to study the fire-resistance performance of cast-in-place composite beams with rigid joint constraints, the temperature rise experiment and numerical simulation of the cast-in-place composite beams with rigid joint constraints were carried out. In the process of the experiment, the experiment phenomenon was observed and recorded in detail, and the temperature distribution and displacement change of the cast-in-place composite beam were measured. Through the analysis of the experimental data, it is found that the temperature distribution of the cast-in-place slab decreases gradually along the direction of the slab thickness, the temperature at the slab bottom is the highest, and the area below 40 mm is most affected by the fire. The cast-in-place slab will delay the temperature rise of the upper flange of the steel beam. Due to the influence of the temperature gradient, the cast-in-place slab will restrain the deformation of the steel beam. Due to the influence of the temperature stress and the load bending moment, the cracks across the slab surface appear at the top along the central axis direction, and the cast-in-place composite beam has strong deformation recovery ability after cooling. The simulation results of cast-in-place composite beams with rigid joint constraints are in good agreement with the experiment results, which verifies the correctness and feasibility of the numerical simulation.