吊顶主次龙骨节点受剪和受弯性能试验研究

近年发生的地震中吊顶的震害显著，主次龙骨节点失效是吊顶破坏的主要原因之一。为评估吊顶主次龙骨节点的受剪和受弯性能，对其开展单调加载和低周往复加载试验，考察了节点的破坏模式、承载力、变形能力、滞回性能和耗能能力，建立了节点的易损性曲线。研究结果表明：主次龙骨节点主轴受剪和次轴受剪的破坏模式分别为节点剪切破坏和节点面外弯曲并脱出，主次龙骨节点受弯的破坏模式是节点脆性脱出破坏。对比节点主轴受剪，节点次轴受剪时强度更低，但节点变形能力更强。对比节点主轴受弯，节点次轴受弯时强度更高，但节点转动能力稍低。主次龙骨节点受剪和受弯时的荷载-位移滞回曲线捏拢效应显著，耗能能力不强。易损性分析表明，主次龙骨节点次轴受剪和主轴受弯时更容易破坏。

EXPERIMENTAL STUDY ON SHEAR AND BENDING BEHAVIOR OF MAIN-CROSS TEE JOINTS OF SUSPENDED CEILING

The suspended ceiling system (SCS) experienced obvious damage during earthquakes in recent years, and the failure of the main-cross tee joints is one of the major reasons for the ceiling damage. A series of tests on main-cross tee joints under monotonic and cyclic loadings were conducted to investigate the shear and bending behaviors of the main-cross tee joints. The failure modes, load-bearing ability, deformation capacity, hysteretic behavior, and energy dissipation capability of the joints were investigated, and the fragility curves of the joints were established. The test results indicate that the failure modes of the main-cross tee joints in the strong and weak axes under shear loading are the shear failure and out-of-plane bending and separation failure of the joints, respectively. The brittle separation from the grid is the failure mode of main-cross tee joints under bending loading. Compared with the shear capacity of the joints in the strong axis, the joint strength is lower but the deformation ability of the joints is stronger in the weak axis in the shear test. Compared with the bending capacity of the joints in the strong axis, the joint strength is greater but the rotation ability of the joints is slightly lower in the weak axis in the bending test. Whether under bending or shearing loadings, the pinching effect of the load-displacement hysteretic curve of the joints is significant, and the energy dissipation capacity is limited. The fragility analysis shows that the main-cross tee joint is more vulnerable when the weak axis of the joint is subjected to a shear force or the strong axis of the joint is subjected to a bending moment.