THE IMPACT OF TORSIONS ON THE OVERALL STABILITY OF CURVED AND COMPRESSED STEEL MEMBERS

This paper presents a study on monosymmetric i-shaped steel members with two simple supported ends subjected to a combination of compression, bending and torsion. Based on force and deformation and equilibrium differential equation, the total potential energy equation is given. By using Rayleigh-Ritz method to solve the total potential energy equation, a series of nonhomogeneous equation are obtained. Two load cases which is uniform load and midspan load respectively, are studied on the influences of torsion on the overall stability, and the influences of mid-span torque on bearing moment, uniform load, midspan load and uniform torsion to bear uniform load on overall stability of curved steel members. The research shows that, the effects of torque can be reflected through the correction of overall stability coefficient of flexural and bending steel members. The calculation is easy and convenient for design. Meanwhile the equivalent critical moment coefficient of the interaction of transverse homogeneous load and concentrated load of steel beams, and the supplementary of design code for current steel structure have been provided. Finally the validation calculation indicated that, the overall stability checking calculation of steel members would tend to be unsafe without considering the effect of torsions.