Fatigue Evaluation and Parametric Study on Orthotropic Steel Deck Composed of a New-Type of U-rib with Upset Webs

Fatigue cracks initiate at rib-to-deck welded joints play a significant part in issues with respect to the durability of orthotropic steel deck bridges. In general, the extremely highly local stress concentration induced by direct application of wheel load and geometric discontinuous are known as the primary reasons for this type of fatigue crack. In the purpose of improving the fatigue resistance of rib-to-deck joints by alleviating local stress concentration, an innovative orthotropic steel deck composed of a new type of U-rib with upset webs was proposed. Fatigue evaluation based on effective notch stress approach for the presented orthotropic steel deck was performed using finite element method. The investigative results indicate that the proposed orthotropic steel decks have preferable fatigue performance than that composed of conventional normal U-ribs. The presented new-type of U-rib is suitable for the enhancement of the structural durability of the orthotropic steel deck. A parametric study also showed that the deck plate thickness, rib wall thickness, and upset thickness have various degrees of effects on the fatigue resistance of the innovative rib-to-deck welded joint.