Shear behaviour of litesteel beams

Abstract: This paper presents the details of an investigation into the shear behaviour of a recently developed, cold-formed steel beam known as LiteSteel Beam (LSB). The unique LSB sections are produced by a patented manufacturing process involving simultaneous cold-forming and electric resistance welding. To date, limited research has been undertaken on the shear yielding and buckling behaviour of LiteSteel beams with torsionally rigid, rectangular hollow flanges. For the shear design of LSB web panels, their elastic buckling strength under shear loading must be determined accurately including the potential post-buckling strength. Currently the elastic shear buckling coefficients of web panels are determined by assuming conservatively that the web panels are simply supported at the junction between the flange and web elements. However, depending on the geometric properties of LSBs, the elastically restrained supports is closer to a fixed support. In the present study, a series of numerical analyses based on three-dimensional finite element modelling was carried out to investigate the shear buckling behaviour of 13 different LSB sections. The results were then evaluated to determine the effects of the important geometric parameters on the resulting support condition at the junction between the flange and web elements. Effects of this improved support condition on the shear capacity of LSBs has been demonstrated by modifying the current AS/NZS 4600 design equations through the inclusion of a higher buckling coefficient. Keywords: LiteSteel Beam (LSB), Shear buckling, Shear yielding, Cold-formed steel structures, Slender web and hollow flanges.