Fatigue resistance of orthotropic steel deck system with double-side welded rib-to-deck joint

Fatigue cracking is a major problem in orthotropic steel decks (OSDs). This study investigated the fatigue resistance of an OSD system with novel double-side welded rib-to-deck joints. The fatigue strengths of the novel rib-to-deck and conventional rib-to-diaphragm joints were determined by fatigue testing two full-scale segmental models. A framework for evaluating the dominant crack mode of an OSD system was then developed and applied; the inner weld toe-deck crack and weld toe-rib wall crack were identified as the dominant crack modes of the double-side welded and rib-to-diaphragm joints, respectively. The nominal and hot spot stress fatigue strengths of the novel rib-to-deck joint were 90.53 and 108.95 MPa, respectively, whereas those of the rib-to-diaphragm joint were 44.27 and 98.66 MPa, respectively.