火灾作用后RC简支梁抗弯承载力试验研究和可靠度分析

Experimental Study on Bearing Capacity and Reliability Analysis of Reinforced Concrete Simple Support Beam after Fire Damage

建筑物发生火灾后 ,结构的力学性能如何变化一直是研究人员普遍关注的热点问题。但是火灾对建筑物的影响因素较为复杂 ,这些问题至今还没有得到很好的解决。笔者通过试验研究了 11根三面受火钢筋混凝土简支梁在不同初始荷载和配筋下的火灾后抗弯承载力和可靠度 ,并进行了比较。试验结果表明 :在其他条件相同仅配筋不同时 ,钢筋配置适当增加 ,火灾后抗弯承载力下降减少 ,钢筋混凝土梁的抗火能力增强 ;在其他条件相同仅初始荷载不同时 ,初始荷载增加 ,抗弯承载力下降增加 ,火灾后可靠度的下降幅度也增加。试验研究为钢筋混凝土梁的抗火设计和火灾后的修复和加固提供了参考依据。

It is a topic of general interest that how the mechanic performance of the structure has changed after the building fire. However, the effects of fire on building are rather complicated and still unsolved so far. Through the test of 11 reinforced concrete simple support beams burned on their three surfaces at different initial load and reinforcement, the bearing capacity and reliability of beams are studied, and their results compared. The experimental result showed that when other conditions are the same and only the ratio of reinforcement is different, with the increase of reinforcement, the fall of bearing capacity of beam flexure resistance decreases and the capacity of beam fire resistance increases. When other conditions are the same and only the initial load is different, with the increase of the initial load, the fall of bearing capacity of beam flexure resistance increases, and the fall of reliability of beam increases too after fire. The results provide the reference basis for fire-resistant design and treatment after the fire.