Buckling of laterally braced beams

This paper reports on thteral buckling tests of H-shaped beams unbraced or braced laterally by purlins or a sub-beam. These tested beams were subjected to uniform moment or moment gradient. The restraining effect of adjacent members, bracing effect of purlins or a sub-beam and effect of moment gradient on load carrying capacity and the post-lateral-buckling behaviour were investigated. Elastic-plastic analysis by means of the finite element method was performed to simulate the experimental behaviour. Analytical results were found to match well with experimental behaviour for the most part. Effective length factors that incorporate the effects of moment gradient, restraining, and bracing into design of H-shaped beams are discussed and proposed, based mainly on the analytical results.