Shear behavior of large stud shear connectors embedded in ultra-high-performance concrete

In this article, the static shear behavior of large-headed studs embedded in ultra-high-performance concrete was investigated by push-out test and numerical analysis. A total of nine push-out specimens with single and grouped studs embedded in ultra-high-performance concrete and normal strength concrete slabs were tested. In the testing process, only shank failure appeared without cracks occurring on the surface of ultra-high-performance concrete slab when the steel–ultra-high-performance concrete specimens reached ultimate shear capacity. The shear capacity of specimens with large studs embedded in ultra-high-performance concrete slab increased by 10.6% compared those in normal concrete, and the current design codes such as Eurocode4, AASHTO LFRD 2014, and GB50017-2003 all underestimate the shear capacity of such kind of steel–ultra-high-performance concrete composite structures according to experimental results. Numerical models were established using ABAQUS with introducing damage plasticity material model. The influence of stud diameter, concrete strength, thickness of clear cover, and spacing of studs on the static shear behavior was thoroughly investigated via parametric analysis. Based on the experimental and numerical analysis, the existence of wedge block and the decrease of axis force are beneficial for improving the shear capacity of stud shear connectors.