Present work deals with the behaviour of steel beams under flexure. The elastic critical moment is an important parameter in design with regard to lateral torsional buckling. However, the complex nature of the lateral torsional buckling phenomenon makes it difficult to accept all the affecting factors and assumptions. Beams experiencing bending about major axis and when compression flange is unrestrained against lateral buckling, the beam may fail by lateral torsional buckling before attaining its bending strength. It can be computed by using commercial programs. Here, finite element freeware LTBeam is used to evaluate elastic critical moment for various cases and relate them with the Codal provisions given in IS 800:2007.

Keywords: Lateral torsional buckling, Finite element method, LTBeam, Elastic critical moment.