Study on the composite mechanism of large Rubber-Sleeved Stud connector

•Push-out tests on large Rubber-Sleeved Stud connectors were conducted.•Failure modes and deformation performance were obtained.•Numerical simulations were carried out to reveal the composite mechanism.•Parametric analysis was performed based on the verified modeling method. The Ordinary Headed Stud (OHS) connector whose diameter is 25 mm or larger is regarded as the large OHS connector, which possesses greater shear stiffness and ultimate capacity. Therefore, it is expected that the required number of OHS connectors can be reduced by applying the large OHS connectors in the steel-concrete interface, which have its construction advantages over smaller ones. However, the great stiffness could also cause the shear force of the large OHS connector at the interface edge exceeding the design allowable value. Hence, the large Rubber-sleeved Stud (RSS) connector was proposed by wrapping rubber sleeve at the root of large OHS connector to decrease its stiffness, making the shear force in the steel-concrete interface more evenly distributed. In this study, push-out tests and numerical simulation were carried out to reveal the composite mechanism of the large RSS connector. Based on the verified modeling method, parametric analysis was performed to investigate the influence of different parameters on the shear stiffness of RSS connectors. The results show that the shear stiffness of large RSS connector is decreased to 41.5% of the large OHS connector. RSS connectors exhibit better deformation recovery and accumulation compared with OHS connectors under cyclic loading. Furthermore, the maximum principal tensile stress of concrete could be decreased and concrete damaged areas are reduced when the large OHS connectors are wrapped with rubber sleeves. The shear stiffness of RSS connector is positively related to the rubber shearing coefficient C10 and concrete compressive strength fcm while negatively related to the rubber sleeve thickness tr, rubber sleeve height hr and rubber compressibility coefficient D1.