预制节段桥梁钢榫键接缝直剪力学性能试验

Experimental Study of Steel Keyed Joints in Precast Concrete Segmental Bridges Under Direct Shear Loading

摘要:

设计8组“Z”型接缝试件，以榫键数量、几何形状、尺寸和接缝类型为试验参数，对钢榫键接缝的力学性能开展试验研究。试验结果显示：方形榫键试件开裂后承载能力较圆形榫键试件更稳定；单键（干、胶），双键（干、胶）接缝相比平面（干、胶）接缝承载能力分别提高3.81倍、43.02%，6.06倍、41.58%；单、双键胶接缝相比其干接缝剪切强度分别提高151.39%、69.68%，但胶接缝出现更明显的脆性破坏；混凝土开裂强度和榫键剪切强度决定了干接缝不同的破坏模式，而胶接缝均出现直剪破坏；胶接缝直剪破坏后接缝剪切抗力由钢榫键和界面摩擦提供，其力学性能类似其干接缝。

Abstract:

Eight groups of “Z” joint specimens were designed to conduct direct shear tests on steel keyed joints. Taking shapes，sizes，numbers of steel keys and joint type as experimental parameters， the mechanical properties of joints were studied. The results show that the stiffness of epoxied joints is superior to that of the dry joints. The epoxied joints have an ultimate shear strength of 151.39%， and 69.68% higher than dry joints， for 1 and 2 steel keys， respectively； while the failure of the epoxied joints is found to be more sudden and brittle. Adding 1 or 2 steel keys to a flat joint， shear strength can be increased 43% and 41.58% for epoxied joints， 3.81 times and 6.06 times for dried joints respectively. The failure modes of the dry joint are determined by the cracking strength of concrete and the shear strength of the steel key， while the epoxied joint appears direct shear failure. When the steel key epoxied joint occurs direct shear failure， the shear resistance is provided by the steel key and friction， and its mechanical properties are similar to the steel key dry joints.