带悬臂梁段的弱轴连接组合节点循环荷载试验研究

Experimental study of weak-axis composite connections with cantilever beam splicing under cyclic loading

为研究组合效应对带悬臂梁段的箱形节点域弱轴连接节点滞回性能的影响,完成了6个梁柱中节点足尺试件在低周反复荷载作用下的破坏试验,对试验现象、滞回曲线、应变分布、耗能及楼板滑移等进行了分析和比较。试验结果表明,相对于纯钢节点,组合节点使得梁中和轴上移,从而增大梁下翼缘焊缝破坏的风险,对梁上翼缘焊缝则可以起到保护作用;组合节点的荷载-位移滞回曲线较纯钢节点的饱满,且承载性能更加稳定,刚度有大幅提升;拼接处翼缘焊缝破坏后,腹板螺栓均出现大量滑移;尽管采用抗剪程度为50%的部分抗剪连接,楼板滑移量均不足0.5 mm,且栓钉在试验过程中均未破坏。另外,耗能能力从滞回曲线包围面积与能量耗散系数两个指标来分析得到了相悖的结论,耗能能力大小的评价方法有待商榷。

In order to study the effect of composite action on the cyclic performance of connections along weak-axis with cantilever beam splicing, full-scale cyclic testing was conducted on six cruciform joint specimens. Detailed test observations, hysteresis loops, strain distribution, energy dissipation capacity, and slab slippage were analyzed and compared experimentally. Based on the test results, it is shown that compared to bare steel joints, the neutral axis of composite joints is shifted obviously, leading to the fracture of bottom flange groove welds, while the protection of the top flange welds. The hysteresis loops of composite joints are more plumb and repetitive, and the bearing capacity is more stable. There is a substantial increase in stiffness. A large amount of web bolts slippage is observed after the fracture of splice flange welds. While the 50% partial shear connection is adopted, the slippage of slab is less than 0. 5 mm, and the studs are intact during the entire testing. In addition, the energy dissipation capacity was analyzed based on two indexes of the area of hysteresis loops and the energy dissipation coefficient. However the conclusions based on the two indexes are opposite, implying that the evaluation method of energy dissipation capacity needs to be discussed.