Experimental and numerical study on welding residual stress of U-rib stiffened plates

Welding residual stress is inherent to welding of U-rib stiffened plates and it is a “fact of life” that must be accounted for by designers. In this study, the welding residual stresses of U-rib stiffened plates were investigated through numerical and experimental methods. The influencing factors on the welding residual stress are based on a) two full-scale residual stress tests and b) a series of numerical parameter analyses. Regarding the U-rib residual stress, the maximum tensile stress decreased as the U-rib thickness increased, whereas an opposite trend is observed for the maximum compression stress. For the subpanel residual stress, the maximum compressive stress increased with the increase of the U-rib thickness, while the maximum tensile stress decreased first and then increased. As the subpanel thickness increased, the maximum residual tensile/compressive stress and the maximum U-rib compressive stress decreased, and the U-rib tensile stress increased. The influence of the subpanel thickness on the residual stress is reduced as the U-rib thickness increased. The material yield strength has a minor effect on the extreme value of the residual stress of the subpanel and has a certain effect on the tensile stress distribution interval. The maximum residual tensile stress of the U-rib is approximately proportional to the material yield strength. According to these results, this study presents a simplified distribution diagram for the welding residual stress of the U-rib stiffened plate. It has been verified that the simplified distribution diagram can provide a valuable reference for the design of steel bridges.