Research on Welding Residual Stress Distribution in Double-Sided Welded U-Rib Steel Bridge Decks Based on Fatigue Cracking Mode

In order to study the influence of residual stress on the fatigue performance of double-sided welded steel bridge decks， the welding process and residual stress distribution of double-sided welded U-rib steel bridge decks were studied by numerical simulations. It examined the effects of parameters on the residual stress distribution for four cracking modes in the roof-to-U-rib connection of double-sided welded U-rib steel bridge decks. Empirical formulas were derived to predict the residual stress distribution under these different cracking modes. The results showed that the transverse residual tensile stress for all four cracking modes exhibited a tension-compression-tension distribution pattern along the thickness direction. The maximum tensile stress observed was 241.5 MPa. For the T1 cracking mode （characterized by crack propagation at the outer weld toe through the plate thickness）， increasing the roof thickness from 12 mm to 20 mm caused the peak compressive stress to rise from 68 MPa to 93 MPa （a 35.8% increase）， while the tensile stress increased from 155.9 MPa to 199.6 MPa （a 28.0% increase）. The U-rib thickness showed minimal effect， but increasing the groove angle reduced both the transverse tensile stress and compressive stress. For the T2 cracking mode （characterized by crack propagation at the inner weld toe through the plate thickness）， the plate thickness had little influence on the peak compressive stress. However， the tensile stress increased from 186.7 MPa to 242.9 MPa， representing an increase of approximately 30.1%. Both the U-rib thickness and groove angle demonstrated negligible effects on the T2 mode.