LOCAL AND INTERACTION BUCKLING OF POLYGONAL SECTION STEEL COLUMNS

The purpose of this paper is to investigate experimentally the local buckling strength and interaction strength between local and overall buckling of closed polygonal section steel columns. A total of 23 specimens was tested to failure under axial compression loading. Seventeen specimens were stub columns with regular rectangular, pentagonal, hexagonal, heptagonal, and octagonal sections. The others were medium-length columns with regular rectangular, hexagonal, and octagonal sections. An empirical formula based on the compression tests is presented to predict local buckling strength and interaction strength between local and overall buckling strengths of closed polygonal steel columns. Edge strain at the maximum stress-and-strain energy is an important standard to estimate the load-carrying capacity of a member same as the maximum stress. A comparison of edge strain and strain energy with equivalent width-thickness ratio is included. They show a similar tendency and decrease with the increase of equivalent width-thickness ratio. Also, they decrease with the increase with the equivalent slenderness ratio.