07.10: Elastic buckling strength of light‐gauge built‐up member from lipped C‐section under compression

ABSTRACT In a cold‐formed steel structures, the plate thickness is thin. Therefore, plates can be connected by drilling tapping screws, or similar processes. Cold‐formed steel structures differs from conventional steel frames in that cold‐formed steel structures does not require welding. This construction method is simple and has excellent workability. In addition, cold‐formed steels can be used in built‐up members having various cross‐sectional shapes by connecting. In particular, built‐up members formed by lipped channel sections are widely used as vertical frame members, because they have a large bending stiffness relative to their cross‐sectional area. The built‐up member that joins the cold‐formed steels back‐to‐back with drilling tapping screws is one among them. When designing a built‐up compression member, it is important to understand the effect of spacing between interconnections and boundary conditions. However, it is not clear whether the connection interval of chord members affects the elastic buckling strength. Therefore, the spacing of connection is given an upper limit. In addition, previous studies have assumed that the cross section of the end is uniformly compressed. Accordingly, other boundary conditions have not been considered. This study considers steel with a thickness of less than 2.3 mm and discusses how spacing between interconnections and boundary conditions influence the elastic buckling strength.