Experimental study on local buckling of 800 MPa HSS welded I-section columns under axial compression

In this study, the experiments of 800 MPa high strength steel (HSS) welded I-section columns under axial compression are performed to investigate their local buckling behavior. The effects of width-to-thickness ratio and slenderness on the local buckling load are considered. Four different buckling modes of columns (i.e., web buckling, flange buckling, web and flange buckling, and global buckling) are designed. The local buckling load obtained from load-displacement curves and load-strain curves are investigated. New embedding coefficients of the web and flange in 800 MPa HSS welded I-sections are recommended. Design provisions in current specifi-cations for predicting the ultimate bearing capacity of 800 MPa HSS welded I-section columns under axial compression are evaluated, and it is concluded that GB50017-2017, AISC360-16, and EN 1993-1-5 is a little overestimated for estimating the ultimate bearing capacity of 800 MPa HSS welded I-section columns under axial compression. A three-dimension finite element model is developed for predicting the ultimate bearing capacity of 800 MPa HSS welded I-section columns under axial compression, which is validated by test data. The effect of residual stress on the ultimate bearing capacity of 800 MPa high strength steel welded I-section columns is not obvious. A more accurate model for estimating the ultimate bearing capacity of 800 MPa HSS welded I-section columns under axial compression is recommended.