Local buckling of 460 MPa high strength steel welded section stub columns under axial compression

• Experiments of 13 welded section stub columns made of 460 MPa steel were conducted.
• A parametric analysis was carried out using a validated FE model.
• Current design methods on the local buckling of 460 MPa stub columns are not accurate.

In comparison to steel sections made from normal strength steel (NSS), those fabricated from high strength steel (HSS) can be thinner and lighter because of the improvement of the steel yield strength. This results in higher width-to-thickness ratios of the component plates and makes local buckling more critical for members in compression. Axial compression experiments were performed on steel stub columns made from Q460 steel (with nominal yield strength greater than 460 MPa), including four box section members and nine I-section members. A finite element model was developed with accurate simulation of initial imperfections. The modeling results were verified by experiments and a parametric analysis was conducted based on the validated modeling. In comparing the ultimate stress calculated by design methods in different codes with the experimental and numerical results, it was found that for the component plates of box section members, the design methods overestimated the ultimate stress of local buckling, so that the result was not safe enough. For the flanges of I-section members, the design methods underestimated the ultimate stress, especially for cases with relatively higher width-to-thickness ratio.