EVALUATION OF AXIAL CAPACITY OF HIGH STRENGTH STEEL COLUMN UNDER ECCENTRIC LOADS

Abstract

Most of the current studies and developments which deal with the effect of eccentric axial compression load, especially at the column, in addition to it affects Columns behaviour with closely spaced transverse reinforcement improves significantly with the use of high-strength confinement steel. The use of larger bar diameters for longitudinal reinforcement produces little beneficial effect on the ductility of column, increasing ratio of longitudinal reinforcement in high strength concrete columns leads to an increase in column capacity but decreases its ductility, tie configuration is very effective in strength and ductility of high strength columns. In general, when axial load increases, the flexural ductility of the column decreases, as eccentricity increases, columns give more ductile behaviour in under and post-peak stage. this paper experimentally investigates the elastic buckling of steel columns with three different area cross-sections of the square cross-sections, different eccentric and two different boundary conditions, i.e. fixed-free(F-F) and pinned-pinned (P-P) boundary conditions, under axial compression. It is concluded that calculations made  the P-P and the lowest differences in F-F at difference buckling load, also the square cross-section of P-P has the lowest slenderness ratios and square cross-section of F-F has the highest slenderness ratios and the buckling loads of P-P column is higher than F-F column.