Fatigue reliability assessment of rib-to-deck double-sided welded joints in orthotropic steel decks considering welding residual stress

Fatigue cracking of rib-to-deck conventional single-sided welded joints is a prevalent issue in orthotropic steel decks (OSDs), significantly impacting their structural integrity and durability. Rib-to-deck innovative double-sided welded joints have the potential to enhance the fatigue resistance of OSD. However, Welding Residual Stresses (WRS) significantly influence the fatigue life of these joints, mandating its consideration in fatigue assessments. This study introduces a novel approach for assessing the fatigue reliability of rib-to-deck double-sided welded joints in OSDs, accounting for the effects of traffic vehicle loading and WRS. Initially, a comprehensive fatigue damage equation for welded joints of OSDs was formulated, integrating WRS and dynamic vehicle loads, utilizing fracture mechanics theory. Subsequently, a measurement-based random traffic model was utilized to derive the vehicle-induced stress spectra at the welded joints. The effects of deck thickness, fatigue crack depth and fatigue crack aspect ratio on the stress intensity factor (SIF) of the crack at the weld toe were analyzed. These three variables were considered as feature vectors for the construction of a polynomial model of the shape functions, which was utilized to calculate the SIF. Finally, the fatigue reliability of the rib-to-deck double-sided welded joints in OSDs subject to traffic vehicle loading considering the WRS was estimated using Monte Carlo simulation. The influence of traffic volume growth on fatigue reliability was discussed. This research underscores the critical role of WRS in the fatigue performance of welded joints in OSDs and offers an innovative framework for assessing the fatigue reliability of steel bridge welds.