Experimental study on shear performance of studs and PBL connectors in steel-HFRC composite beams

This paper first conducts a study on the shear performance of studs and perfobond leiste (PBL) connectors in steel-hybrid fiber reinforced concrete (HFRC) composite beams through static push-out tests, exploring the influence of different steel beam section forms and concrete types on their shear performance. Subsequently, based on existing theories and calculation methods, the shear stiffness and ultimate shear capacity were calculated and analyzed respectively. The research results indicate that the push-out specimens connected with studs and PBL connectors ultimately exhibit a composite failure mode. The different section forms of steel beams exert no significant influence on the failure mode, shear capacity, ultimate slip, and slip ductility coefficient of specimens connected with studs. In specimens with PBL connections, having a relatively larger number of perforated steel plates tends to induce a greater number of crushing cracks in the concrete slab, leading to a reduction in its shear capacity and ultimate slip, while increasing the slip ductility coefficient. PBL connectors exhibit relatively higher shear capacity and plastic deformation capacity compared to stud connectors. The application of HFRC demonstrates superior mechanical properties and crack resistance compared to normal concrete (NC), not only reducing damage to specimens but also enhancing their shear capacity. The initial stiffness and average stiffness of both types of connectors can be calculated using the 0.2 mm and 2 mm secant stiffness methods, respectively. Furthermore, a comparative analysis has been conducted regarding the applicability and accuracy of existing calculation methods for the shear capacity of each connector type.