When a steel beam is designed for lateral-torsional buckling, the elastic critical moment Mcr is an important design parameter. The factor that is considered for Lateral-torsional buckling is point of action of load. In this study, Double symmetric I-section, monosymmetric I-section and built-up I-section beams are considered for rotation around the minor axis and warping considering various load heights and varying degrees of end restraint. Various beam lengths and different forms of load with centric loading, beams with a channel cross-section are examined. Mcr (elastic critical moment) is determined using software and compared to values obtained using an empirical expression called the 3-factor formula in EC3 and the IS 800:2007.
The disparity between the software tools under investigation is due to the different methods and assumptions used to calculate Mcr. SAP2000 and STAAD.Pro are the software tools used in this report.