Finite element modelling of push-out tests for novel locking nut shear connectors

Abstract

Steel-concrete composite beams have been used in bridge construction for decades. Novel demountable bolted shear connectors, that allow bridge disassembly and offer high level of prefabrication, are proposed for the connection of the deck with the steel beams, as an alternative to the conventional headed studs. In terms of sustainability, bolted shear connectors facilitate the replacement of deteriorating bridge components and therefore extend the bridge design life. Despite their effectiveness, research on steel–concrete composite beams with bolted shear connectors is limited. In order to expand the available literature, this paper develops a three-dimensional finite element model to investigate the behaviour of a novel demountable shear connector for precast steel–concrete composite bridges. The connector uses high-strength steel bolts, which are fastened to the steel beam with the aid of a special locking nut configuration that prevents the slip of the bolts within their holes. The accuracy of the proposed FE model is validated by comparing its predictions with the experimental results available in the literature. Once validated, the FE model was then used to conduct a parametric study to evaluate the effect of bolt height, diameter and tensile strength, bolt pretension and the compressive strength of concrete on the load-slip behaviour, the shear resistance, the slip capacity and the stiffness of the shear connectors.