Numerical Study of Moment Capacity of Cold-Formed Steel Built-Up Box Beam with Self-Drilling Screw Connection

The structural behavior of Cold-Formed Steel (CFS) built-up beam sections have been extensively investigated by numerous researchers. Most existing studies focus primarily on the use of screws solely to assemble two channel profiles into built-up sections. This study proposes the use of self-drilling screws for connecting two separated segments of CFS built-up box beam. These box beams are assembled from two channel sections C 75×35×0.75 placed face-to-face. Their flexural strength is investigated by two methods: experiment, and Finite Element Analysis (FEA). The experiment comprises by means of four-point flexural test at simple beam with lateral restraint at support. This study involves a two-stage experimental test, where at the first stage, beams are tested without any connection, and the second stage employs beam with a connection. FEA models have been developed and compared to the experimental results. It is shown that the FEA models can accurately predict the behaviour of CFS built-up box beams with and without connections.