Numerical analysis and design method of Y-shaped connectors encased in UHPC for prefabricated composite bridges

Abstract

In this paper, the shear mechanism of the novel Y-shaped (Y-S) connector encased in ultra-high-performance concrete (UHPC) was analyzed to reveal the steel-concrete interface separation mechanism and the interaction mechanism between the connector and UHPC. Subsequently, a validated finite element (FE) model was established for parametric analysis to investigate the effects of strength parameters and structural parameters on the shear performance of the Y-S connector, including the yield strength of the steel plate and penetrating rebar, the compressive strength of the concrete and UHPC, the diameter of the penetrating rebar, the effective width and thickness of the steel plate, and the dimensions of the UHPC shear pocket. The design method for the Y-S connector was finally developed and validated, including the improved shear capacity model, the shear stiffness model, the peak slip model, and the method for calculating the load-slip curves. The results indicate that the UHPC dowel in the holes experiences triaxial compressive stress, and the penetrating rebar undergoes deformation under the force from the top and bottom UHPC. The yield strength of the steel plate, as well as the effective width and thickness of the steel plate, have remarkable effects on the shear performance of the Y-S connector compared with other parameters. These analytical models can well predict the shear performance of the Y-S connector in the required precision range.