The behavior of steel-concrete-steel sandwich composite beams with box-profile shear connectors: Experimental and numerical

Abstract

This study investigated the flexural behavior of new box-profile (BP) shear connectors in composite steel–concrete-steel (SCS) structures. To this end, nine beam specimens were fabricated and tested to evaluate the flexural and shear behaviors of BP shear connectors. The effects of geometric parameters, including the concrete core thickness, steel faceplate thickness, and shear connector thickness and width, on the flexural strength of BP shear connectors were then analyzed and reported. According to the results, increasing the shear connector width increased the rigidity of the beam, leading to a stress concentration in the slot welds. Therefore, the slot welds failed, leading to the detachment of the faceplate from the core. Increasing the strength of the concrete core above 40 MPa not only did not improve structural behavior but also led to BP shear connectors failing earlier than the concrete core, with the beam experiencing shear failure. Beams with 25≤hcontc≤30 and 3.33≤hconbc≤5 showed higher composite behavior. Finally, the beams were numerically modeled and validated using the nonlinear finite element method (FEM). A sensitivity analysis was conducted, and the concrete core strength and shear connector arrangement contributions were discussed.