Full-scale push-out testing of headed stud-steel block connectors in prefabricated steel-concrete composite beams

Abstract

Full-scale push-out tests of 13specimens were conducted to study the shear behavior of the headed stud-steel block connectors (HSBCs) in prefabricated steel-concrete composite bridge beams, where the key parameters of steel block height, longitudinal connector spacing, presence of oblique rebars in the precast slab, and grouting material were considered. The objective was to develop large shear stiffness, high shear capacity, and sufficient deformability of the connectors in prefabricated steel-concrete composite bridge beams. The results from the push-out tests reveal: two main failure modes the compression failure in the concrete slab and the shear failure in the grouting material and concrete slab; and the HSBC has large shear stiffness, high shear capacity (≈1500kN), and sufficient deformability. Based on the analysis of the shear extrusion dimension of the grouting material and concrete slab, the shear inclination ratio was found approximately to be 1:5, which agrees well with the stipulation specified in the EC4. The height and spacing of HSBCs are the two principal parameters affecting the shear capacity and failure mode of the specimens. By comparing the measured shear capacities of the HSBCs with those calculated by the design formulas for steel blocks and headed studs as specified in the EC4, it is shown that the steel block and headed studs can work together to resist the force between the precast concrete slab and the steel beam.