Shear behaviours of steel-HSFRC welded stud and perfobond rib connectors under static push-out experiments

Abstract

In this study, high-strength fibre-reinforced concrete (HSFRC) was introduced into steel–concrete composite girders owing to its high strength, good cracking, and impact resistance. Sixteen push-out specimens were tested to study the shear behaviours of the welded stud and perfobond rib connectors used in steel-HSFRC composite girders. The failure modes, load–slip curves, and shear behaviours of the push-out specimens were analysed and compared. The experimental results indicate that the shear capacity and stiffness of these two types of connectors are improved when they are used in steel-HSFRC composite girders, whereas the ductility of the welded stud and one-hole perfobond rib connectors decreases. The stud diameter has a significant effect on the shear behaviour of welded studs, unlike the stud length. The shear capacity of perfobond rib connectors increases with an increase in the perforating rebar diameter and hole number. The initial stiffness and ductility of perfobond rib connectors were larger than those of welded stud connectors with similar shear capacities. Finally, shear capacity prediction equations for welded studs and perfobond rib connectors embedded in HSFRC are proposed and verified to have good accuracy and applicability.