T形圆钢管节点受弯抗震性能试验研究

Experimental study on seismic behavior of CHS T-type tubular joints under bending

为了研究T形圆钢管节点受弯抗震性能,进行了支主管直径比不同的2个节点受循环往复弯矩作用下的试验研究。试验结果表明:节点主要耗能方式为主管管壁的塑性变形和裂纹扩散,在试验后期还有一部分耗能来自支管根部管壁的塑性变形;最终破坏模式为节点域主管管壁延性撕裂破坏;节点的荷载—相对位移滞回曲线饱满,开裂后节点承载力逐渐下降,裂纹延性扩散,表现出良好的抗震耗能能力。试验所得的极限承载力比规范计算值高了20%~33%。对比2个节点的试验数据及结果,发现支主管直径比较大节点的延性和耗能能力均比支主管直径比中等节点的更好。

In order to study the flexural seismic performance of circular hollow section(CHS)T-joints,the cyclic bending moments of two joints with different brace-to-chord diameter ratios are tested.The experimental results show that the main energy dissipation mode of the joint is the plastic deformation of the chord wall and crack propagation and a small part of the energy dissipation is due to the plastic deformation of the brace root in the late stage of the test.The final failure mode of the two joints is the ductile tearing of the chord wall within the joint-zone.The load-relative displacement hysteresis curve of the joint is full,the bearing capacity of the joint decreases gradually and the crack ductility spreads after cracking,showing good seismic energy dissipation ability.The ultimate bearing capacity obtained by the test is about 20%-33%higher than that calculated by the code.By comparing the experimental results of the two joints,it is found that the ductility and energy dissipation of the joint with larger brace-to-chord diameter ratios are better than those with medium brace-to-chord diameter ratios.