Fatigue Damage Evaluation of Orthotropic Steel Deck Considering Weld Residual Stress Relaxation Based on Continuum Damage Mechanics

Abstract

Weld residual stresses (WRSs) in orthotropic steel decks (OSDs) contribute prominently to fatigue damage. WRSs relax during the accumulation of fatigue damage. However, their effects are ignored in conventional methods of fatigue damage evaluation. This paper presents the first evaluation approach to fatigue damage that considers of the relaxation of WRSs. WRSs were analyzed using a thermomechanical analysis that took into account the relaxation of WRS. An elastic–plastic fatigue damage model was developed using continuum damage mechanics. The proposed model of fatigue damage was experimentally validated using fatigue tests on U-rib weld connection specimens under different cyclic loading conditions. The test results indicated the feasibility of the elastic–plastic fatigue damage model for predicting WRSs and fatigue damage in OSDs. Ignoring the effects of WRSs may result in the overestimation of fatigue life, resulting in structural designs that are not conservative enough.