带加劲肋顶底角钢梁柱连接节点试验研究

Experimental investigation on behavior of stiffened top and seat angle beam-to-column connections in steel frame

为了研究带加劲肋顶底角钢梁柱连接节点受弯性能与抗震性能,分别进行了5个不同构造的角钢连接试件的单调加载试验和4种带加劲肋角钢连接试件的循环加载试验。单调加载试验结果表明:节点在负弯矩作用下,仅增设顶角钢加劲肋能够较大幅提高节点初始转动刚度与荷载,破坏模式为加劲肋处焊缝脱开;仅增设底角钢加劲肋对节点初始转动刚度影响较小,但能够增加节点的荷载。采用循环加载试验分别考察了4种不同构造的加劲肋角钢连接节点的破坏机制、滞回曲线、延性、耗能、以及刚度。结果表明:加劲肋顶底角钢连接节点是一种典型的半刚性、部分强度连接,具备良好的转动能力和耗能能力,节点破坏模式为角钢与加劲肋处呈弧状塑性铰断裂,极限弯矩对应的层间位移角均在0.04 rad以上,可满足美国规范FEMA 350不小于0.03 rad的延性设计要求。在加劲肋试件达到层间位移角0.08 rad时,节点还能够承受0.5Mmax以上的弯矩。

In order to investigate the moment resistance and seismic behavior of the stiffened bolted top-and-seat angle connection under higher pretension force in high-strength bolt, five specimens for monotonic loading and four specimens for cyclic loading were tested. Tests of the monotonic loading of negative bending moment show that a stiffener weld in tension zone of the angle of the joint can greatly enhance connections and initial rotational stiffness and strength, but crack is found in the weld zone of stiffener. When a stiffener is applied to the compression zone of the angle, it has almost no effect on the initial rotational stiffness, but increases the plastic moment of resistance of the connection. Tests on cyclic behavior and failure mechanisms were investigated on four different configurations of connections. The M-O curves, skeleton curves, ductility, energy dissipation and rigidity were evaluated. The results show that stiffened top and seat angle connections behave as typical semi-rigid and partial strength connection with good rotation ability and energy dissipation. Crack is found alone the arc platic line. The ultimate rotation is greater than 0. 04 rad, which satisfies the ductility requirement of American standard FEMA 350. When the inter-story drift ratio of stiffened specimens reaches 0. 08 rad, the joints could bear a moment above 0. 5Mmax, indicating the connection has certain robustness.