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

为了研究外包U形钢混凝土组合梁和方钢管混凝土柱连接节点的抗震性能，进行了5个外包U形钢-混凝土组合梁与方钢管混凝土柱连接节点的拟静力试验，包括2个外环板节点和3个内隔板节点。通过研究节点试件破坏模式、滞回曲线、骨架曲线和核心区剪切变形等，进一步分析节点试件的承载能力、延性和耗能能力等抗震性能。研究表明：节点试件加载过程中经历了由弹性、弹塑性到塑性的发展过程；核心区混凝土密实节点试件的滞回曲线更为饱满，延性较好，耗能能力强；外环板节点试件延性要优于内隔板节点试件，耗能能力更强；核心区混凝土不密实的内隔板节点试件具有良好的延性，但承载力显著降低，施工中应严格控制核心区混凝土的浇筑质量，或者在节点核心区采用厚度较大的钢板来提高其延性和承载力。

Cyclic loading tests of composite joints between concrete-filled square steel tubular column and composite beam with U-shaped steel girder

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.