Shear behavior of perfobond connectors in the steel-concrete joints of hybrid bridges

The perfobond connector is the most widely used connector in the steel-concrete joint, and its shear behavior is different from that of perfobond connectors in steel-concrete composite beams. However, because of the limitations of the parameters considered in previous tests and the difficulty of measuring the internal stress states of test specimens, the force transfer mechanisms of perfobond connectors in steel-concrete joints remain unclear. To clarify shear behavior of perfobond connectors in the steel-concrete joints of hybrid bridges, an effective finite element model of push-out testing is developed. Finite element analysis results indicated that: the dilatancy effect of concrete dowel causes concrete cracking, and the shear capacity of connectors is mainly controlled by the confinements of structural reinforcement in they direction. In the case of weak confinements from structural reinforcement, the confinement effects of friction force at the bottom of a specimen significantly affects the mechanical properties of concrete dowels. Pressure fields can slightly enhance the shear capacity of connectors, whereas tension fields can significantly reduce the ultimate shear capacity of connectors. With an increase in confinements, the shear and tension forces of the perforating rebar in the ultimate state gradually shift toward pure shear forces. Because of the separation of steel-concrete interfaces caused by the dilatancy of concrete dowels, the contribution of interface bond friction to the shear capacity of connectors should be considered as a safety reserve. (C) 2020 Elsevier Ltd. All rights reserved.