Experimental and numerical investigation on cold-formed steel semi-oval hollow section compression members

Abstract

A comprehensive experimental and numerical investigation on cold-formed steel semi-oval hollow section pin-ended columns was performed and is presented herein. The semi-oval hollow sections investigated in this study are composed of one semi-circular flange, one flat flange and two flat web plates. Four cross-section sizes were included and a total of 19 tests was conducted under concentric loading with different specimen lengths in the test program. A finite element model was developed and validated against the test results. The numerical model is capable to replicate the test results. Upon the validation of finite element model, an extensive parametric study was performed consisting of 200 numerical data cases, which cover a wide range of cross-section geometries and column slenderness. The results obtained from experimental program and numerical study were compared with the predicted strengths by the existing and modified Direct Strength Method. Reliability analysis was conducted to assess the reliability of the design methods. The comparison results show that the existing Direct Strength Method generally provides conservative predictions, but the predictions are scattered for slender sections. Modification was proposed to address this issue. The modified Direct Strength Method provides accurate and less scattered predictions in a reliable manner. The modified Direct Strength Method is suitable for cold-formed steel semi-oval hollow section columns, especially for short column members and columns with slender sections.