Rewelding Residual Stress of Fatigue Crack at U-Rib-to-Deck of an Orthotropic Steel Deck

Abstract

The orthotropic steel deck is a prevalent stiffening girder structure utilized in long-span cable-stayed bridges and suspension bridges. Nonetheless, the issue of fatigue cracking has persisted in in-service orthotropic steel decks, significantly impacting the longevity of bridges. This study examines the analysis of the distribution of residual stress during the rewelding process of a fatigue crack at the U-rib-to-deck-plate joint of an orthotropic steel bridge deck. Additionally, the impact of the initial welding and the stiffness of the boundary constraint on the residual stress field during rewelding is discussed. The findings indicate that the removal of the fatigue crack prior to rewelding alleviates the transverse residual stress caused by the initial welding. After undergoing the rewelding procedure, both the transverse residual stress and the longitudinal residual stress exhibited a significant stress peak. More precisely, the transverse tensile stress underwent a rise from 21 MPa to 385 MPa, while the longitudinal tensile stress experienced an increase from 345 MPa to 525 MPa. Furthermore, the range of tensile stress within the longitudinal residual distribution expanded by 88%. Moreover, the stress redistribution during the rewelding of the local fatigue crack varied depending on the constraints imposed on the steel bridge deck. Notably, the transverse residual stress increases by 40.6% when compared to the absence of constraints. The findings of this research offer valuable insights for the implementation of rewelding repair techniques on steel bridge decks, emphasizing the significance of considering the effects of residual stresses induced during the rewelding process.