Experimental study on buckling strength of stub-column with box section made of SBHS700

High performance steel SBHS (Steels for Bridge High Performance Structure) has been introduced in Japan recently with three strength grades, 400 MPa, 500 MPa, and 700 MPa. The mechanical characteristics of SBHS include high yield strength, toughness, and great weldability due to its fine microstructure. However, few studies have been conducted on the relatively new SBHS. Therefore, the objective of this study is to examine the local buckling strength and the buckling behavior of a stub-column with box section made of SBHS700 through conducting the uniaxial compression test. The width-to-thickness ratio parameter is designed to be the limiting value described in the ultimate strength curves. In terms of the experimental results, the load, displacement, and strain at different locations are investigated to understand the local buckling phenomena. The out-of-plane deformation as well as the progression of the strain measured at both sides of the plate are used to show the plate buckling phenomena. Large out-of-plane deformation was found after reaching the yield load near the maximum load due to plate buckling. Moreover, the local buckling strength of the test specimens with the limiting width-to-thickness ratio parameter made of SBHS700 was found to be possible to be evaluated based on the current ultimate strength design curves.