Flexural performance of steel-UHPC composite beams with shear pockets

The steel-UHPC composite beam shows many advantages over its conventional steel-concrete counterpart. In this paper, the flexural performance of large-scale steel-UHPC composite beams composed of a precast UHPC slab, which is connected to the steel girder by large-headed stud clusters embedded with shear pockets, were investigated through a four-point bending test. According to test results, no splitting cracks are observed in UHPC shear pockets, and no concrete crushing occurs on the surface of the UHPC slab at the failure of beam specimens. The UHPC and steel exhibit good composite action, and the flexural performance of steel-UHPC composite beams are significantly improved. Based on the results of the experimental test, a formulation considering the tensile strength of UHPC is proposed for predicting the ultimate flexural capacity of the steel-UHPC composite beams. In addition to experiments, a validated numerical model is developed to further investigate the shear behavior of large-headed stud clusters. The effect of the compressive strength of UHPC shear pockets, the compressive strength of UHPC slabs, and the tensile strength of steel girders on the flexural performance of the steel-UHPC composite beam were investigated through a parametric study.