火灾后圆形孔蜂窝组合梁受力性能研究

Study on the stress performance of honeycomb composite beams with circular holes after fire

圆形孔蜂窝组合梁火灾后的力学性能研究,可为受火后建筑结构性能评估提供参考依据。对4根火灾后圆形孔蜂窝组合梁及1根未过火处理圆形孔蜂窝组合梁开展静力加载试验,分析火灾、加劲肋设置、开孔率等因素对圆形孔蜂窝组合梁破坏形态、抗弯刚度及承载能力的影响。结果表明:降低开孔率可以提高火灾后圆形孔蜂窝组合梁的抗弯刚度和极限承载能力;设置加劲肋的火灾后圆形孔蜂窝组合梁与未设置加劲肋的构件相比,其极限承载能力提高了6.9%;火灾前、后,圆形孔蜂窝组合梁在静力荷载作用下均发生弯曲破坏,但火灾后其开裂荷载、极限承载能力和延性均出现不同幅度的下降;提出了具有良好精度的圆形孔蜂窝组合梁火灾后剩余抗弯承载力的计算方法。

The study of the mechanical properties of circular-hole honeycomb composite beams after fire can provide reference basis for the evaluation of building structures after fire.Static loading tests were carried out on four pieces of honeycomb composite beams with circular holes after fire and one honeycomb composite beams with circular holes without fire,so as to study the effects of fire,stiffener,and porosity on failure forms,flexural stiffness and load-bearing capacity of honeycomb composite beams after fire.The results indicate that:the flexural stiffness and ultimate load-bearing capacity of honeycomb composite beams can be improved by reducing the porosity.Compared with those without stiffeners,the ultimate load-bearing capacity of the honeycomb beam with circular holes after fire is increased by 6.9%.Before and after fire,the honeycomb composite beams with circular holes all bend and fail under static load,however,after the fire,the cracking load,ultimate load-bearing capacity and ductility are all decreased by different magnitudes.The calculation method of residual flexural capacity of honeycomb beam with circular holes after fire is proposed,which boasts high accuracy.