钢-混凝土可拆卸螺栓连接件受剪性能研究

Shearing performance of demountable steel-concrete bolt connector

为快速地维修和更换钢-混凝土组合桥梁的混凝土板,提出了可拆卸组合梁螺栓连接件,即锥形铸铁螺栓连接件(tapered iron bolt connector,TIBC)。通过两组推出试验对TIBC的受剪性能进行研究,分析结果表明:TIBC的破坏形式大多以下部高强螺栓剪坏为主,故破坏后仅需更换下部高强螺栓即可;由于锥形铸铁块的存在,TIBC的周边混凝土可以承受较大局部荷载;TIBC的剪切强度为下部高强螺栓抗拉强度的75%,可按栓钉承载力公式进行结构设计;相同强度和直径下,TIBC的初始刚度较普通螺栓连接件明显提高,且初始刚度离散性较小;下部高强螺栓直径为16 mm的试件比直径为12 mm的试件滑移性能好。

In order to make the concrete slab of the concrete-steel composite bridge easy to be repaired and replaced, this paper presented a novel demountable composite beam bolt connector, called tapered iron bolt connector(TIBC for short).The shear performance of TIBC was studied through two groups of push-out test. The results show that failure mode of TIBC is mostly the failure of lower high strength bolt, so it only needs to replace the lower high strength bolt. Due to the existence of conical cast iron blocks, the surrounding concrete of TIBC can bear a large local load. The shear strength of TIBC is 75% of the tensile strength of the lower high-strength bolt, and the structural design can be carried out according to the formula of the bearing capacity of the stud connectors.With the same strength and diameter, the initial stiffness of TIBC is significantly higher than that of ordinary bolt connector, and the initial stiffness is less discrete.The specimens with the diameter of 16 mm lower high-strength bolt have better slippage performance than those with the diameter of 12 mm.