方钢管混凝土柱-外包U形钢混凝土组合梁节点抗震性能试验研究

Five composite joints with concrete-filled square steel tubular column and composite beam with U-shaped steel girder were tested under low cyclic loadings. These members included 2 exterior diaphragms composite joints and 3 interior diaphragms composite joints. The seismic behavior of the composite joints including shear capacity, ductility and energy dissipation were assessed by examining their failure modes, hysteretic curves, skeleton curves and shear deformation of panel zone. The experimental results show that all composite joints experience elastic, elastic-plastic and plastic stages during the loading process. Besides, the composite joints with compacted concrete in panel zone tend to show plump hysteretic curves, good ductility and high energy dissipation, especially for the exterior diaphragms joints. Although the interior diaphragms joints with uncompacted concrete in the panel zone are more ductile than those members with compact concrete, their shear capacity decreases significantly. Therefore, concrete casting quality in the panel zone should be controlled strictly. Another good way is to apply thick steel tube to improve the shear capacity and ductility of the joints.