Failure characteristics of cold-formed steel built-up sections with web stiffeners under axial and eccentric compression

To seek high load-carrying capacity members, built-up sections of Cold-formed steel (CFS) have been the popular choice. While most of the studies focused on the built-up sections with plain channel sections (with or without lips), few studies have been reported for the built-up sections with channel sections with web stiffeners, particularly also considering the eccentric loading and web openings. This paper presents a total of 44 new experimental results comprising 22 built-up sections with V-stiffeners and 22 with Sigma-stiffeners of four different member lengths under the axial and eccentric compression loading to reveal the potential failures and load-carrying capacity of these built-up sections. The measurements of initial geometric imperfections and tensile coupon tests were conducted before compression tests. Following the test program, the experimental results provided the details of the buckling behavior and failure modes and a set of load response curves. The failure modes and impact of a variety of member parameters on the buckling behaviors and axial strengths were analyzed and discussed. The study herein revealed the failure characteristics of these built-up sections under axial and eccentric loading and provided preliminary test results for further expansion and computational model development.