Elastic, Lateral‐Torsional Stability of Beams: General Considerations

Abstract

The paper presents a more accurate solution for the elastic, lateral‐torsional buckling of I‐beams under unequal end moments which incorporates accurately the effects of moment gradient, lateral end restraint, and beam slender‐ness. Since lateral‐torsional buckling involves warping and torsional modes of deformation, the proposed approach treats the problem as the superposition of two hypothetical cases of beam buckling corresponding to zero warping and zero torsional rigidity. The effects of moment gradient and lateral end restraints are considered independently on each mode and then superimposed to obtain the critical moment of the combined mode. The proposed analytical model is used to derive new parametric expressions for moment modification and effective length factors as design aids.