Experimental and numerical studies on fatigue performance of orthotropic steel deck with open-ribs and key-shaped cutouts

This paper examines the fatigue performance of an orthotropic steel deck (OSD) with open-ribs and key-shaped cutouts through a full-scale segment fatigue test and numerical simulations. The investigated fatigue details include the rib-to-deck welded joint, rib-to-crossbeam welded joint, crossbeam-to-deck welded joint, and the edges of the cutouts in the crossbeam. Experimental results indicate that fatigue cracks formed at the bottom of the deck plate, the flange of the longitudinal rib, and the crossbeam-to-deck welded joint, with equivalent stress amplitudes of 145 MPa, 145 MPa, and 113 MPa at two million cycles, respectively—values exceeding those specified in Eurocode 3. The overall fatigue performance of the OSD specimen with key-shaped cutouts was found to be comparable to that with apple-shaped cutouts. A detailed finite element model of the OSD specimen was developed using ABAQUS and validated against experimental data. In addition, to enhance fatigue performance, four variations of cutout shapes were proposed, and their corresponding stress responses were analyzed and compared. Numerical results revealed that connecting the crossbeam and longitudinal rib at the upper side of the key-shaped cutout with a vertical edge effectively reduced the stress responses of the concerned fatigue details, which therefore improved the fatigue performance. This study highlights the reliability of OSDs with key-shaped cutouts and supports their potential application in large-span bridge structures.