Design of Cold-Formed Steel Built-Up Closed Sections with Intermediate Stiffeners

Ultimate load-carrying capacity of cold-formed thin-walled columns with built-up box and I section under axial compression

“…In Young's study [5] on built-up closed section columns, the test strength was compared with the nominal design strength obtained by using DSM, in which the buckling stress is obtained by using single section, single restrained section and double sections with the flange thickness two times the web thickness. Stone's study [6] on built-up I section formed with two channels and screw attachments and Wilson's study [7] on box section composed of two C-section members in contact by seam weld showed that AISI provision about the strength of built-up compression members is conservative on an average for thin members and exceedingly for thick members.…”

Numerical investigation and design of cold-formed steel built-up open section columns with longitudinal stiffeners

“…A built-up section having edge and web stiffeners is expected to have better performance to resist against local and distortional buckling compared to sections without stiffeners. Young and Chen [4] investigated the cold-formed steel built-up closed sections with web stiffeners compression members and Zhang and Young [5] conducted a series of column tests on cold-formed steel built-up open sections with edge and web stiffeners. However, limited research has been reported on such kinds of structural members.…”

07.13: On extending the direct strength method to the design of cold‐formed steel built‐up columns

“…A brief review of the recent progress in relevant research and developments is outlined in the following as a precursor for presenting the concepts of the methodology developed. In a study on CFS built-up closed section with intermediate stiffeners by Young and Chen [3], the obtained test strengths were compared with design capacities determined using the DSM. Three different sections were analysed, namely, the single section, single section restrained at the flanges, and double section with the flange thickness two times the web thickness, and it was shown that assuming no interaction between component profiles results in acceptable, but conservative estimations.…”

“…The finite element method (FEM) as the dominant numerical approach in computational mechanics has been successfully employed for the analysis of CFS built-up sections [8][9][10]. The semi-analytical finite strip method (S-a FSM) with some simplifying assumptions about inclusion of fasteners and built-up section geometry [3,4,11] has also been used for the buckling analysis of intermittently connected CFS sections. However, the adopted assumptions may not represent the actual effect of discrete fasteners and may fail to accurately capture the level of composite action.…”