2017 Annual Stability Conference Presentation
Session SS2A – Stability of Thin-Walled Columns Tuesday, March 21, 2017 3:15 pm
Buckling and Collapse Behavior of Screw-Fastened, Built-Up Cold-Formed Steel Columns of Varying Cross-Section Size: Experimental Investigation
An ongoing experimental effort using built-up cold-formed steel (CFS) columns is discussed in this paper. The quantification of partially-composite action, determination of member end fixity, and observation of buckling and post-buckling behavior is presented. The cross-sectional shape studied is a common back-to-back, lipped channel section with two self-drilling screw fasteners connecting the webs of the individual sections along their length. Sixteen different cross-section sizes are chosen, where each section is tested with two web fastener layout types as determined via AISI S100 (2016) section I1.2. A total of 32 monotonic, concentric compression tests are completed, and results show a vast range of deformation behavior, with local-global interaction and flexural-torsional modes common in many of the sections. Also, the column end conditions are determined to be semi-rigid, but almost fully-fixed for all sections. Ongoing work includes nonlinear FEA modeling validated by test data and a new design approach using finite strip-based modeling and the Direct Strength Method.
David C. Fratamico and Benjamin W. Schafer, Johns Hopkins University, Baltimore, MD; Kim J.R. Rasmussen, University of Sydney, Sydney, NSW, Australia