Steel-Yielding Demountable Shear Connector for Composite Floors with Precast Hollow-Core Slab Units

Abstract

A demountable shear connector for use in composite floors with precast hollow-core slab units is proposed. The proposed shear connector consists of a steel square hollow tube welded on a steel plate that is bolted on the steel section’s top flange using four high-strength bolts. Concrete is cast only around the connector, allowing for an easy separation of the precast slab units from the steel sections during the deconstruction phase, with operations required only from the top of the composite floor. The shape of the hollow tube promotes a ductile elastic-plastic behavior under the longitudinal shear flow in a composite beam. Ten push tests using a horizontal testing arrangement were carried out to assess the structural performance of the novel shear connector. The experimental results show that the shear connector has a stiffness comparable to that of a welded shear stud, strength that can be adjusted to achieve the desired degree of shear connection in a composite beam, and slip capacity that is much higher than the requirements of the current codes of practice. A finite-element model was also calibrated against the tests and found capable of accurately reproducing the experimental behavior. The finite-element model was then used to conduct a number of parametric studies to safely generalize the experimental results. Based on the experimental and numerical results, a design model is proposed to predict the strength of the demountable shear connector based on either the yielding of the steel tube or the failure of the precast slab.