In this paper, nonlinear finite element method was applied to evaluate welding residual stresses in box columns. In this study, thermal and mechanical analysis of weld was carried out to investigate the residual stresses. The thermal analysis was performed to obtain the thermal history, which was used as a loading in the mechanical analysis of the column. For investigating the effect of welding sequences on residual stresses, four possible welding sequences of columns were investigated. Afterwards, the optimal sequence which has the least residual stress was selected. Furthermore, the impacts of the residual stresses on the compressive strength of columns was studied. The results show that the evaluated axial deformation of the short columns with considering residual stresses is twice higher than the displacements without considering the effect of these stresses. In the slender columns, the achieved axial deformations with considering residual stress effects were 15% higher, and the ultimate strengths were 11% lower than those computed with ignoring the effect of residual stresses.

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