Numerical investigation of welding residual stresses in orthotropic steel decks for fatigue damage prognosis

Orthotropic steel decks (OSDs) are vital infrastructure components that distribute vehicle loads efficiently while facilitating smooth passage for both vehicles and pedestrians. However, these structures are prone to fatigue damage, particularly at deck-to-rib (DTR) and rib-to-diaphragm (RTD) joints under repeated traffic loads. Welding, a key fabrication process, introduces residual stresses and geometric irregularities that influence fatigue behavior. This paper investigates the effect of welding on OSD fatigue using transient thermo-mechanical analysis in ABAQUS. The model focuses on a single weld of the specimen, incorporating welding-induced thermal and mechanical effects to analyze stress distributions and identify fatigueprone locations at DTR and RTD joints. A comparison between models with and without welding effects reveals that welding noticeably alters stress concentrations at these critical locations, affecting fatigue life predictions. These findings emphasize the importance of including welding details in fatigue assessments for reliable structural performance evaluation. This work highlights the role of thermo-mechanical modelling in enhancing the understanding of fatigue behavior and improving OSD structural integrity assessment.