Compressive behavior of built-up closed box section columns consisting of two cold-formed steel channels

摘要: Abstract Thirty specimens of built-up closed box sections consisting two cold-formed steel channels various cross (B92 and B143), lengths (3000, 1500, 450, 270 mm), thicknesses (1.2 1.5 mm) were tested subject to concentric eccentric axial compression. Failure modes analyzed load vs. displacement curves obtained. The test results indicate that the failure long medium columns compression are flexural buckling about weak axis, whereas short column is excessive local buckling; strong axes exhibited flexural-torsional buckling, respectively. Finite element (FE) models established verified. Detailed parameter studies performed evaluate accuracy code equations for a wide range parameters. FE analysis strength decreased with an increase in slenderness ratio or web height-to-thickness ratio; increasing flange width can significantly stability column; axis faster than axis. Finally, effectiveness design methods, i.e., effective width-to-thickness method Chinese code, method, direct resistance factor North American specifications predict this type evaluated. For B92 series B143 greater 92, it conservative use methods calculate column. Additionally, columns.