扩大十字形截面型钢混凝土柱-SRC梁节点抗震承载力试验研究

提出了内置扩大正、斜向十字形截面型钢混凝土柱-工字钢型钢混凝土（SRC）梁节点的构造方式。通过对4个内置扩大正十字形和斜向十字形截面的型钢混凝土柱-SRC梁节点试件和1个内置普通十字形截面型钢混凝土柱-SRC梁节点试件的低周反复荷载试验，研究了试件的破坏特征、滞回曲线、骨架曲线、剪切变形和钢材应变，分析了配钢形式、加载角度和构造措施（直接焊接、竖向隔板连接）对节点受力性能的影响，并在此基础上对节点核心区受剪承载力进行了计算。试验结果表明：上述两种新型截面型钢混凝土梁柱节点均发生节点区剪切破坏，达到极限状态时，节点区箍筋及型钢腹板应力均达到屈服强度，试件型钢及翼缘框内混凝土仍能承担较大荷载，并趋于稳定；新型SRC梁柱节点核心区剪力-剪切角滞回曲线饱满，无捏缩现象，其受剪承载力比相同破坏模式的普通型钢混凝土梁柱节点试件大；柱内采用斜向布置十字型钢以及梁柱正交时，节点试件的剪切承载力更大，所提出的两种构造措施对节点承载能力影响不大。

Experimental study on seismic bearing capacity of steel reinforced concrete beam-column joints with enlarging cross-shaped section steel

Joint details of steel reinforced concrete (SRC) column with enlarging and diagonal cross-shaped steel and steel reinforced concrete (SRC) beams with I-shaped steel were proposed. Failure patterns, hysteretic characteristic, skeleton curves, shear deformation and steel strain of SRC beam-column joints were researched by tests of four new and one common specimens under low-cycle reversed loading. Meanwhile, effects of steel shape, load angel and structural details on mechanical properties of joints were analyzed. The ultimate shear capacity of joints was also calculated. The test results show that shear failure is occurred for SRC beam-column joints with new-type section steel. The stress of stirrup and steel web in the core region can reach yield strength, and steel and concrete of core region can bear larger load and tend to be stable at the ultimate state. The shear force-shear angle hysteretic loops of new-type SRC joints are in pump shapes and have no significant pinch, whose shear capacity is higher than that of SRC joints with ordinary cross-shaped steel. The shear capacity of joints is superior when the diagonal cross-shaped steel is contained and beams cross columns obliquely, and the two structural details proposed have little effect on shear capacity of SRC beam-column joints.