Distortional buckling of thin-walled lipped channel partially restrained with attached theathing subjected to bending

Cold-formed thin-walled steel members with thicknesses of around 1mm are relatively new structural members in Japan. It is because such a thin steel member had not been long allowed to use as a structural member under the Japanese Building Standard Law. This situation has been changed in recent years through the development of steel-framed houses. Although the use of such a thin steel member is currently possible, there are still some design issues to be clarified for realizing the broader applications, mainly related to its complex buckling behavior. The complex buckling is called distortional buckling and is often seen in the floor and roof panels in steel-framed houses. To study the behavior of distortional buckling in detail therefore, negative bending tests were conducted in this paper for panels consisting of two lipped-channels and structural plywood fastened together with screws. Twelve bending tests provided detailed behavioral information on distortional buckling and the possible strength evaluation methods for improving the design of thin-walled steel members