Experimental study of exterior beam-to-column composite joint with precast concrete slab and demountable embedded bolted shear connector

Abstract

In steel-concrete composite floor systems, welded stud shear connectors attached to the steel beam and embedded in the concrete slab prevent separation of components of the steel-concrete composite beam and hinder the reuse of these elements at the end of the structure's service life. In recent approaches, concrete slabs are typically connected to steel beams using bolted shear connectors. The utilisation of bolted shear connectors enables the reuse of structural elements during renovation or retrofitting. This study experimentally investigates the behaviour of an exterior beam-to-column composite joint with bolt shear connectors embedded in grout and a precast concrete slab under static loading. Five full-scale beam-to-column joints were tested. Four specimens had precast concrete slabs and bolt shear connectors embedded in grout, while one specimen served as a control without a concrete slab. The investigation focused principally on two key parameters: the degree of shear connection and the reinforcement ratio of the precast concrete slab. Additionally, this study investigated the influence of the concrete slab on beam-to-column joint behaviour, revealing that the degree of shear connection and the slab's reinforcement ratio are significant determinants of the joint's structural performance. Increasing these parameters enhanced the flexural capacity of the joint. Furthermore, the flexural capacity of the steel beam-to-column junction was increased by adding a precast concrete slab. Finally, a simplified model for determining the flexural moment capacity of beam-to-column composite joints has also been proposed and investigated. © 2025 Elsevier Ltd