Flexural cracking behavior of reinforced UHPC overlay in composite bridge deck with orthotropic steel deck under static and fatigue loads

•Static and fatigue cracking behavior of R-UHPC overlay in UHPC-OSD systems are tested.•Cracking behavior of R-UHPC overlay in transverse and longitudinal directions are studied.•Nominal cracking strength of R-UHPC overlay of composite bridge decks is evaluated.•Fatigue resistance of R-UHPC overlay of composite bridge decks is determined. Ultra-high performance concrete (UHPC) has been used to enhance the fatigue resistance of orthotropic steel decks, but the enhancement effect is compromised by UHPC cracks in negative moment regions. This research investigates the flexural cracking behavior of reinforced UHPC (R-UHPC) overlay in composite bridge deck under static and fatigue loads. The investigated behavior included the load-carrying capacity of composite deck, and the cracking process, pattern and resistance of the R-UHPC overlay. Ten composite specimens were tested, including five slabs for the transverse behavior and five beams for the longitudinal behavior. Static tests investigated the load-carrying capacity, strain distribution and nominal cracking strength. Fatigue tests investigated the cracking process and fatigue resistance of R-UHPC overlay. The fatigue process included an internal force redistribution stage (less than10% of fatigue life) and a stable stage (greater than90% of fatigue life). The fatigue resistance of R-UHPC overlay was evaluated with a modified Goodman diagram.