LATERAL-TORSIONAL AND DISTORTIONAL BUCKING OF CHANNEL-SECTIONS AND HAT-SECTIONS

For thin-walled sections, lateral and lateral-torsional buckling are often affected by distortion of the section and this can severely reduce the critical stress. A calculation method for the critical stress which takes account of distortional effects, based on Generalised Beam Theory (GBT), is presented in this paper. The limiting slenderness at which distortional effects begin to take effect is evaluated for channel-and hat-sections on the basis of parametric studies. Approximate formulae for the limiting slenderness are then given.