门式刚架构造改进型节点试验研究

Experimental Research on Improved Joints of Portal Frames

通过对门式刚架梁柱改进型和常规螺栓端板竖放连接节点的低周往复加载试验,对试件的承载力、滞回曲线、刚度退化和等效粘质阻尼系数及破坏模式等进行研究,且分析了试件破坏的原因。结果表明:经过构造改进的圆弧形整体式和弧形加腋螺栓端板竖放节点比常规节点,向下极限承载力均提高21.4%;刚度损伤明显减小;极限荷载时节点域变形较小,避免了高三轴应力作用下节点的脆性破坏;试件SP-2延性和耗能性能明显得到改善,塑性转角满足延性刚架要求。

Study on the bearing of capacity, hysteretic loop, stiffness degradation and failure pattern was made by low cyclic load testing on the steel beam-to-column joints. The joints include three specimens, which are a whole joint, a haanched joint and a common end-plate joint. The test result shows that the ultimate load of the improved structures increases by 21.4 % as compared with the common one from upper side, and the cumulated damage stiffness is much smaller, and the concentration stress relieves better than the common one in the same loading. The deformation of node area is much smaller and avoids the brittleness destruction under the stress triaxiality space. The ductility and energy of SP-2 is much better than SP-1, and the plastic hinges of SP-2ioint meet the requirement of ductility frame.