Mechanical behavior of perfobond connector group in steel–concrete joint of hybrid bridge

Abstract

The perfobond connector is the most widely used connector in the steel–concrete joints of long-span hybrid bridges, and the behavior of the perfobond connector group directly determines the reliability of the connection and the smoothness of force transmission of the joint. However, the existing model test can only reveal some of the connector group’s information in the joint, which leads to the force transfer mechanism of the joint group remaining unclear. To solve these problems, establishing the numerical and theoretical models is necessary. Numerical analysis shows that the stress of the connector on the steel beam loading side is far greater than that on the concrete loading side at the initial stage of loading, and the connector has enough slip capacity to ensure the uniform distribution of interface shear when it reaches the limit state. The reduction of connector spacing weakens the effective support on the concrete dowel and then reduces the shear capacity. In terms of theoretical analysis, four factors determine the interface slip distribution: the length of the steel–concrete joint, the interface stiffness, the axial stiffness of concrete members and the axial stiffness of steel members. The increase of the interface stiffness and the steel–concrete joint length can decrease the maximum slip and reduce the effective utilization ratio of the connector group. When the axial stiffness of concrete or steel members tends to be the same, the effective utilization ratio of the whole group of connectors can improve. Finally, the simplified calculation formula of the maximum slip Smax, the effective utilization ratio μj of the connector group and the load ratio ξj of the connector are put forward.