Inelastic Lateral-Torsional Buckling of Beam-Columns

A procedure for the determination of the inelastic lateral-torsional buckling strength of steel wide-flange beam columns is presented. The beam columns are subjected to axial thrust and to moments applied at one and only. The end moments cause bending about the strong axis of the members, and the effects of initially present symmetric thermal residual stresses are included in the analysis. Two simultaneous differential equations with variable coefficients are derived, awl the corresponding finite difference equations are presented. The coefficients in these equations represent the pertinent section properties that vary along the length of the member in those portions that are partially yielded. The critical end moments are obtained when the value of the characteristic buckling determinant becomes zero.