Flexural behaviour of steel–concrete–steel beams with one-end welded box-profile connectors: effect of overlap ratio

This study investigates the flexural behaviour of steel–concrete–steel (SCS) beams using one-end welded box-profile (BP) shear connectors, proposed as a simpler alternative to conventional double-welded connectors. The overlap ratio – the ratio of connector length to concrete core thickness – was varied (0.6, 0.7, 0.8 and 0.9) to evaluate its influence on structural performance. Four full-scale beams were tested under three-point bending, and corresponding finite-element (FE) models were developed in Abaqus/Explicit software for validation. Results showed that increasing the overlap ratio improved stiffness, load capacity and energy absorption, promoting ductile behaviour. The beam with a 0.7 overlap ratio exhibited the most efficient performance, achieving about 17% higher ultimate strength and twice the energy absorption compared to the lowest ratio. FE simulations closely matched the experiments, with an average strength ratio of 0.98, confirming the model’s reliability. Compared with traditional double-welded connectors, the one-end welded configuration demonstrated comparable strength but with simpler and more economical fabrication. Unlike previous studies focused on shear behaviour, this research highlights the bending performance of one-end welded BP connectors, providing practical insights for the design and optimisation of future SCS systems.