Experimental Study on Longitudinal Shear Behavior of Prefabricated Steel–Concrete Composite Beams with Hidden Continuous Channels and Shear Key Connections

Abstract

A full-depth deck panel (FDDP) system incorporating hidden continuous channels has emerged as a promising solution for accelerated composite bridge construction. However, the system has faced implementation challenges stemming from fit-up issues, particularly the interference between stud connectors and protruding bottom transverse reinforcement. This paper proposes an innovative deck-to-girder connection detail, addressing these concerns through the incorporation of normal-strength concrete (NSC) or ultrahigh-performance concrete (UHPC) shear keys along the hidden channels as a substitute for projecting bottom transverse reinforcement. Furthermore, four-point bending tests were conducted to assess the longitudinal shear performance of the improved precast deck panel systems. Experimental results revealed that shear keys effectively resisted longitudinal shear stress and maintained the composite action between steel girders and concrete slabs, functioning equivalently to the bottom transverse reinforcement. Steel fiber–reinforced keys created with UHPC grout substantially elevated the structural stiffness by mitigating the longitudinal splitting of precast panel systems. Moreover, insufficient top transverse reinforcement can induce premature splitting along the rows of stud connectors, and inadequate bottom transverse reinforcement may provoke longitudinal shear failure along the surfaces passing around shear connectors. Notably, the novel joint details allow for precast deck panel systems erected through the full-span precast method (FSM), which offers improved construction efficiency and structural integrity.