Influence of side-length ratio on high strength concrete-filled RHS tubes subjected to axial load

Based on experimental results of 21 short and 6 slender concrete-filled rectangular hollow section (RHS) tubes subjected to axial load, the influence of height-to-width ratio varied from 1.0 to 1.6 on the behaviors of the columns has been analyzed. The experimental results show that with high steel ratio, the longitudinal stress-strain relationship curves in the two side-length directions are very near before reaching ultimate bearing capacity, and the ductility decreases with the increase of the side-length ratio. The local buckling phenomenon of steel plate is more obvious with higher side-length ratio. The side-length ratio has little influence on deflection curves.