Experimental study on web crippling strength of hollow flange channels under end-one-flange and interior-one-flange load cases

Abstract

LiteSteel beam is a hollow flange channel made from cold-formed steel using a patented manufacturing process involving simultaneous cold-forming and dual electric resistance welding. LiteSteel beams are currently used as floor joists and bearers in buildings. However, there are no appropriate design standards available due to their unique hollow flange geometry, residual stress characteristics and initial geometric imperfections arising from manufacturing processes. Recent research studies have focused on investigating the structural behaviour of LiteSteel beams under pure bending, predominant shear and combined actions. However, web crippling behaviour and strengths of LiteSteel beams still need to be examined. Therefore, an experimental study was undertaken to investigate the web crippling behaviour and strengths of LiteSteel beams under end-one-flange and interior-one-flange load cases. A total of 23 web crippling tests were performed and the results were compared with the current AS/NZS 4600 and AISI S100 design standards, which showed that the cold-formed steel design rules predicted the web crippling capacity of LiteSteel beam sections very conservatively under endone- flange and interior-one-flange load cases. Therefore, suitably improved design equations were proposed to determine the web crippling capacity of LiteSteel beams based on experimental results. In addition, new design equations were also developed under the direct strength method format. This article presents the details of this experimental study on the web crippling behaviour and strengths of LiteSteel beams under end-one-flange and interior-one-flange load cases and the results.