Modeling of fatigue failure mode in U-rib to deck joints in orthotropic bridge structures

Various fatigue failure modes (i.e., cracking position and orientation with respect to a weld) can develop in welded rib to deck connections in orthotropic bridge deck structures. After demonstrating its effectiveness in correlating fatigue test data covering different failure modes, the master S-N curve method was then adopted in this study for determining the critical failure mode in welded U-rib to deck connections. These include considerations of additional failure modes potentially present in double-sided welds between U-rib and deck versus the traditional single-sided weld design. The effects of weld penetrations and test loading conditions on failure mode development have been quantitatively established by means of the master S-N curve method.