Effect of moment gradient on the strength of litesteel beams

A new cold-formed hollow flange channel section known as LiteSteel beam (LSB) has been developed recently in Australia. Due to its unique geometry, it is subjected to lateral distortional buckling, which reduces its member moment capacity for intermediate spans. Although new member moment capacity rules have been developed to allow for this in the case of uniform moment, the effect of non-unifom moment distribution is unknown. Equivalent uniform moment distribution factors are commonly used in the design codes to accommodate the effect of non-uniform moment distributions for conventional hot-rolled, doubly symmetric I-beams subject to lateral torsional buckling. However, their applicability to LSBs is not yet known. This paper presents the details of a finite element analysis study into the effects of moment gradient on the lateral buckling strength of simply supported LSBs and describes the important results in relation to the current design methods