Welded Rib-Deck (RD) joints in orthotropic steel bridge decks are complex structural details prone to different fatigue crack mechanisms. The present work investigates the fatigue life of RD joints using, in a nodal force-based framework, the structural strain damage model formalized in the ASME Div Code [1]. A previously published experimental study [2] of a series of RD welded joint specimens with insufficient weld penetration is investigated. Standard methods such as the nominal stress and the hot spot stress approaches fail to capture the stress concentration at weld root, resulting in non-conservative fatigue life predictions. The equivalent structural stress (ESS) method introduced by Dong [3], later reformulated in a mesh-insensitive nodal-force based framework [4], effectively addresses the four dominating crack mechanisms observed in the rib-deck welded joints of Orthotropic Steel Bridge Decks: • Type 1: fatigue cracks forming at weld toe and propagating into the deck plate • Type 2: fatigue cracks forming at weld root and propagating into the deck plate • Type 3: fatigue cracks forming at weld toe and propagating into the rib plate • Type 4: fatigue cracks forming at weld toe and propagating into the deck plate However, the ESS method tends to provide overly conservative fatigue assessments for the specimens described in [2] as it overlooks the effects of plastic strain redistribution. This study investigates the possibilities offered by the equivalent structural strain. A modified algorithm to account for strain hardening effects is adapted from Pei [5] to treat all four types of potential crack mechanisms and results in a significant improvement in terms of fatigue life predictions. The proposed algorithm can be relevant for the remaining life assessment of older constructions designed with insufficient requirements in terms of weld penetration. REFERENCES [1] Boiler, A. S. M. E., and Pressure Vessel Code. "Sec VIII, Div. 2 (ASME BPVC-VIII-2 e2007)." New York, NY: American Society of Mechanical Engineers (2007). [2] Janss, J. "Fatigue of welds in orthotropic bridge deck panels with trapezoidal stiffeners." Journal of Constructional Steel Research 9.2 (1988): 147-154.