Experimental and numerical investigation on the overall buckling behavior of Q460 high strength steel welded I-section columns

An experimental program including 7 welded I-section steel column specimens was conducted to investigate the overall buckling behavior of Q460 high strength steel axial compression members, and the initial geometric imperfections and sectional residual stresses in the members were measured. Furthermore, their buckling deformation and overall buckling capacity were analyzed. The finite element model was then established and validated by experimental results. In addition, the overall buckling strengths of such Q460 high strength steel welded I-section columns with various sectional dimensions and lengths around both the strong and the weak axis were calculated by using the validated model. It was found that the finite element results were significantly higher than the design curves, indicating that the buckling strength of such high strength steel welded I-section columns was improved compared to those conventional steel columns with normalized slenderness. Finally, the column design curve was suggested according to the current design codes, and based on the finite element analysis a new column curve was proposed by a nonlinear fitting, which can provide valuable information for engineering application and design theory for such advanced steel structures.