Analysis of shear stress for curved composite steel box girders with corrugated webs based on theory of shells of revolution

To accurately calculate the vertical shear stress of curved composite steel box girders with corrugated webs and quantify the contribution of each component effect, a calculation method of shear stress was proposed, which simultaneously considered the flexural resistance of corrugated steel webs, initial curvature, and curvature variation along the girder width. Based on the theory of shells of revolution, analytical formulas for shear stress were derived, including the components of bending, free torsion, restrained torsional warping, and distortional warping. The governing differential equations were established by the energy variational method and solved by the finite difference method. Through parametric analysis of structural horizontal curvature, loading position, and cross-sectional dimensions, the distribution laws and key characteristic indices of shear stress for this type of curved girder were clarified. The results indicate that the analytical values agree well with the experimental values in the literature and the finite element values. Compared with conventional methods ignoring the influence of curvature, the proposed method improves the calculation accuracy of free torsional shear stress and distortional warping shear stress by 5.0% and 13.8%, respectively. When the ratio of girder horizontal curve radius to girder width (R/B) is less than 10, the bending-torsion coupling effect is significant, while it is negligible when R/B≥70. It is suggested that 10 and 70 be taken as the key thresholds to judge whether the bending-torsion coupling effect is significant or negligible. The eccentric load coefficient of shear stress obtained by the proposed formulas is 1.33, indicating that the eccentric load effect is significant and should be emphasized in design. If the restrained torsion and distortion effects are ignored, the calculated total shear stress of the outer web is conservative, but the average error reaches 3.3%-9.0%, indicating that the effects of both should be included in the refined analysis. The established analytical formulas and obtained laws can provide a theoretical reference for the design and calculation of curved composite steel box girders with corrugated webs.