Buckling of Laterally or Torsionally Restrained Beams

A theoretical study is made of the elastic lateral buckling of simply supported, bisymmetrical I-beams provided with a central brace capable of supplying either lateral or torsional restraint. Loading consisting of either equal end moments, a central load, or a uniform load is considered and the effects of variations in the level of application of both the applied loading and the lateral restraint are considered. For torsional restraints it is shown that one relationship between increased stability and restraint stiffness is sufficient to describe all cases considered, while for lateral restraints, where variations in loading are found to exert a much greater effect upon the behavior of the restrained beam, several simple expressions are proposed.