Lateral Buckling of Constrained Beams

The lateral buckling strength of many flexural members designed to resist wind loading is greatly increased by the lateral constraint of the tension flanges provided by the attached structure. Graphs are presented which enable designers to quickly evaluate the effect of this constraint and further to evaluate the additional effect of torsionally fixing the member compression flanges. Within the practical range of parameters these combined effects can raise the buckling strength by a factor of at least 2.7 and possibly as great as 10. The method of solution of the buckling equations used is sufficiently general and straightforward so that solution of rigid frame buckling for a variety of constraints and load distributions can be carried out with a desk calculator.