Experimental and numerical study on the behavior of axially compressed high strength steel columns with H-section

High strength steel (HSS) columns have been located in the research scope of the introduction of multiple column curve to the design codes. However, the determination of current design curves for predicting the maximum strengths of centrally loaded columns was mostly based on the experimental and analytical studies of mild carbon steels. Due to some test data (e.g. residual stress distribution) of HSS columns were not available, the selection of the design curves for HSS columns was inevitably based on some assumptions which need the further confirmation of experiments. In this paper, an experimental study on the ultimate strength of welded H-section columns fabricated from flame-cut steel with the nominal yield strength of 460 MPa under axial compression was conducted. This experiment program include six welded H-section columns with varies slenderness form 40 to 80. The nominal thickness of flanges and webs are 21 mm and 11 mm. A nonlinear finite element model considering the actually measured geometric imperfections and residual stresses was established and used to perform an extensively parametric study. The purpose of the experimental and numerical studies is to find an appropriate design curve for welded 460 MPa HSS H-section columns. By comparing the theoretical curves with the design curves specified in Eurocode3 and GB 50017-2003, it is found that the currently adopted design curves can be extend to welded H-section columns fabricated from flame-cut 460 MPa HSS plates. But the curve c of Eurocode3 is very conservative when H-section columns are buckling about weak axis.