Shear Performance and Ultimate Bearing Capacity Calculation Methods for the Composite Shear Connector

This paper aims to explore the shear properties of the stud + perforated bar (PBL) and stud + arc-shaped reinforcement (ASR) composite shear connectors in steel-ultrahigh performance concrete (UHPC) composite structures; the failure patterns, shear stiffness, and ultimate bearing capacity are investigated; the effects of stud diameter, concrete strength, and thickness of the perforated steel plate and ASR diameter are analyzed. Results show that the two kinds of composite shear connectors present the stud yielding, and the UHPC slab surface exhibited one distinct vertical crack for the stud + PBL composite shear connector and two obvious vertical cracks for the stud + ASR composite shear connector. Both the shear stiffness and shear capacity of the stud + PBL composite shear connector change linearly with the stud diameter; however, quadratic and linear variation trends are presented for the thickness of perforated steel plate, respectively. The shear stiffness and shear capacity of the stud +ASR composite shear connector are dominantly controlled by the diameter of ASR when the diameter of the stud is smaller than that of the ASR. For the shear capacity, the factor of the stud diameter is greater than the thickness of the perforated steel plate for the stud +PBL composite shear connector, while the influence of the ASR diameter is greater than the stud diameter for the stud + ASR composite shear connector. The ductility of the stud +PBL composite shear connector is better than that of the stud + ASR composite shear connector. Calculation formulas for the shear bearing capacity of the two composite shear connectors are in good agreement with the test and finite element analysis results. The research results provide a theoretical basis for the interface optimization design of steel-UHPC composite structures.