Restrained Torsion Analysis of Box Girders with Corrugated Steel Webs Based on Reissner’s Principle

To analyze the restrained torsion effect of the box girder with corrugated steel webs (CSWs) more reasonably, the calculation formulas of warping normal stress and shear stress were deduced considering the accordion effect of CSWs. Moreover, the governing differential equation for analyzing the restrained torsion was established using Reissner’s principle, and the warping coefficient formula differing from Umanskii’s second theory was presented. The calculation formulas were then verified through a numerical simulation of a simply supported box girder, and the influence of web thickness and cantilever slab width on cross-section stresses of the box girder was analyzed. The results show that the stresses calculated based on Reissner’s principle are in better agreement with the finite element solution than those based on Umanskii’s second theory. The ratio of warping coefficient calculated by Umanskii’s second theory to that calculated by Reissner’s principle can reach 4.70. CSWs mainly bear shear stress and almost no warping normal stress, while top and bottom slabs bear both warping normal stress and shear stress. Therefore, more attention should be paid to top and bottom slabs to prevent oblique cracks. In addition, growing web thickness can reduce warping normal stress. With the increase of the cantilever slab width, warping normal stress decreases when the cantilever slab width ratio is above 0.10, while the total shear stress hardly changes when the cantilever slab width ratio is above 0.30.