Application of contour method for residual stress analysis of large and complex cross-sections in civil engineering

The study employs the contour method to determine two-dimensional longitudinal residual stress distributions in large and complex welded cross-sections widely used in the civil engineering industry. Measurements include T-joints, orthotropic steel decks with U-shaped stiffeners, and box sections with plate thicknesses varying between 4 mm and 16 mm, while maximum characteristic cross-sectional dimension is 600 mm. Results indicate stress peaks near welds exceeding the yield strength of the base material, while the effect of additional processes such as hot rolling, thermal cutting, and cold-forming are also evaluated. Statistical analysis confirms the reliability of contour method results, with standard deviations comparable to X-ray diffraction and hole-drilling techniques. Firstly, measurement results are applied for validating finite element models (FEM) developed for manufacturing simulation. In addition, novel residual stress models, satisfying the requirement for equilibrium of internal forces and bending moments, are developed for welded T-joints, OSDs, and box sections, incorporating manufacturing parameters such as heat input, filler material strength, and steel grade. These contour method-based residual stress models provide economic prospects for improving load-bearing capacity predictions of welded structures in advanced FEM-based design.