Influence of stiffening ribs on warping stress of the thin-walled steel box beam

To reduce the warping stress of the thin-walled steel box beam subjected to restrained torsion, transverse stiffening ribs are set. The warping stress is calculated by the finite element software ANSYS considering the influence of the stiffening ribs of the thin-walled box beam with different forms and different spacing intervals. There are four different stiffening rib´s forms to be analyzed and compared. It can be concluded that the stiffening ribs with hollow rectangle section can significantly reduce warping stress in the thin-walled box beam and save the materials at the same time. The other conclusion is the warping stress in the thin-walled box beam will decrease remarkably only when the spacing interval of the stiffening ribs is less than one fifth of the beam length. These conclusions provide references for how to design and layout the stiffening ribs when designing thin-walled box beam in restrained torsion in the practical construction.