A new cold-formed steel beam, called the LiteSteel Beam (LSB), has found many applications in the building industry. When LSBs are used as built-up sections, they are likely to improve their moment capacity and thus expand their applications further. The built-up sections can also reduce the detrimental effects of the Lateral Distortional Buckling (LDB) that occurs with the single LSB sections. However, the behaviour of built-up beams is not well understood. Many steel design codes include guidelines for connecting two channels to form an I-section, and the required longitudinal spacing of connections. But these rules were found to be inadequate in some applications. Therefore a research project was undertaken to investigate the flexural behaviour of back to back LSBs with various longitudinal connection spacings under uniform moment conditions. Elastic buckling and nonlinear finite element analyses were carried out using ABAQUS. The results were compared with corresponding results from experiments and finite strip analyses to validate the numerical model. This paper presents the details of the development of an ideal numerical model of back to back LSBs, its validation and the results.
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