Abstract:In this study, in order to accurately calculate the torsional vibration frequencies of box girder bridge with corrugated steel webs(CSWs), the formulas of polar moment of inertia, torsion constant and warping torsion of box girder with CSWs are proposed. Torsional vibration frequency equation of the box girder with CSWs is deduced based on the D'Alembert's principle considering the Saint-Venant torque and warping torque. The formula of torsional vibration frequency is obtained according to the boundary conditions of simply supported girder. Then, the scaled girder model is fabricated, and dynamic test is carried out to obtain the natural frequencies and corresponding mode shapes of the scaled girder model. In the finite element model of the PC box girder bridge with CSWs, the method of the rigid connection between the corrugated steel webs and concrete flanges is proposed. Comparison between the results of the indoor model test and ANSYS finite element analysis verify the effectiveness of the formula. Finally, the effects of the Saint-Venant torque and warping torque on the torsional vibration frequencies on simply supported composite box girder bridge with CSWs are analyzed. The results show that the warping torque has significantly effects on the torsional vibration frequencies of this type of bridge, while the Saint-Venant torque has little effects.