Fatigue performance of profiled steel sheeting–concrete bridge decks subjected to vehicular loads

•Establishing a deflection calculation model for composite slabs based on discontinuous stiffness.•Analysing the fatigue performance of the composite interface for the Khartoum Al-Halfaia bridge.•Giving suggestions for improving the fatigue performance of composite slabs. Bridge decks are usually formed from profiled steel–concrete composite slabs, which consist of steel and concrete. Slip occurs at the interface between the concrete and steel, which results in unique mechanical and fatigue properties of the composite slab. The objective of this study is to investigate the mechanical and fatigue performance of profiled steel sheeting–concrete bridge decks subjected to vehicular loads. A new method for calculating the deflection of profiled steel sheeting–concrete composite slabs based on a discontinuous stiffness is proposed, and the deformation and internal force components of composite plates are deduced theoretically. The midspan deflection and end-slip calculated via this method are close to the experimental values. With a focus on the fatigue performance of the bridge deck, this paper discusses the fatigue design method of the composite slab and presents fatigue-check calculations for the Khartoum Al-Halfaia bridge over the Nile. A parameter analysis of the composite slab bridge was performed. The effects of the thickness and section geometry of the profiled steel plate and the strength grade and thickness of the concrete on the fatigue performance were investigated, and corresponding improvement measures were examined. It was found that the thickness and geometry of the section significantly affect the shear-stress amplitude of the plate end interface, while the concrete strength grade has little influence on the fatigue performance of the composite slab.