新型钢混螺栓连接件抗剪性能试验

在钢混组合梁桥中，为实现混凝土板与钢主梁的装配式连接，提出一种主要由长螺栓、短螺栓及螺栓连接套筒组成的新型钢混螺栓连接件，该螺栓连接件的最大优势为易于混凝土板的拆卸。设计并开展新型螺栓连接件推出试验（3组试件），并分析各直径螺栓连接件的剪力-滑移曲线特征及相应推出试件的破坏形态；研究新型螺栓连接件的抗剪承载力、峰值滑移及抗剪刚度等力学性能，并与焊钉连接件相应的力学性能进行比较。研究结果表明：推出试验中新型螺栓连接件的破坏形态均为螺栓杆被直接剪断，螺栓连接套筒下侧混凝土仅出现微小裂纹，混凝土无压溃剥落现象；新型螺栓连接件的抗剪承载力约为螺栓杆抗拉强度的80%；钢混结合面的峰值滑移随螺栓直径的增大而增加，M27螺栓连接件的峰值滑移接近6 mm；螺栓连接件的抗剪刚度主要受螺栓杆和螺栓孔间隙的影响，随间隙的增大而减小；在钢混组合梁桥中应用该新型螺栓连接件时，为减少螺栓连接件的使用数量，推荐采用较大直径的螺栓连接件。

Experiment on Shear Performance of Novel Steel-concrete Bolted Connector

To realize the assembled connection between concrete slabs and steel main girders in a steel-concrete composite bridge, a novel steel-concrete bolted connector, mainly composed of a long bolt, short bolt, and connecting nut is proposed. The greatest advantage of this bolted connector is the convenience of disassembling the concrete slabs. Push-out tests on the novel bolted connector with three diameters were designed and implemented. The characteristics of the shear-slip curves for each bolted connector were analyzed, including the failure mode of the corresponding push-out specimen. The mechanical performance including shear capacity, peak slip, and shear stiffness were discussed and compared with the corresponding mechanical performance of welded stud connectors. The results show that, in the push-out tests, the failure mode of the novel bolted connectors is that the bolt shanks are directly cut off, and there are only slight cracks in the concrete on the underside of the connecting nut without crushing and peeling phenomenon. The shear capacity of the novel bolted connector is approximately 0.8 times its tensile strength. With the increase of the bolt shank diameter, the peak slip at the steel-concrete interface in each push-out test increases, and the peak slip of M27 bolted connectors is close to 6 mm. The shear stiffness of the bolt connector is mainly affected by the clearance between the bolt shank and bolt hole, but this effect decreases as the clearance increases. If the novel bolted connectors are to be used in steel-concrete composite bridges, large-diameter bolted connectors are recommended to reduce the number of bolted connectors.