Flexural Behavior and Design of the New Built-up LiteSteel Beams

A new cold-formed steel beam, known as the LiteSteel Beam (LSB), has the potential to transform the low-rise building industry. The new beam is effectively a channel section with two rectangular hollow flanges and a slender web, and is manufactured using a simultaneous cold-forming and electric resistance welding process. Built-up LSB sections are expected to improve their flexural capacity and to increase their applications. They are also likely to mitigate the detrimental effects of lateral distortional buckling observed with single LSB members of intermediate spans. However, the behaviour of built-up beams is not well understood. Currently available design rules based on longitudinal connection spacing limits and doubling the capacity of single members were found to be inadequate. Therefore a research project based on both experimental and advanced numerical studies was undertaken to investigate the flexural behaviour of back to back LSBs with various longitudinal connection spacings under a uniform moment. This paper presents the details of the experimental and numerical studies and the results