BEHAVIOR OF CFDST COLUMNS WITH OCTAGON AND POLYGON STEEL SECTIONS

Abstract

Based on some findings on the two kinds of Concrete Filled Double Skin steel Tube (CFDST) members with circular or square sections, a new kind of CFDST with octagonal and polygonal section have been investigated under axial and cyclic loading. For this purpose, the outer steel wall has various steel shapes and the inner steel wall is the same as circular section and for some part of analyses, the outer tube is the same as circular section and the inner wall has various steel sections. Primarily, FEM procedure has been verified with some available experimental studies and then, seven composite columns with different section types have been analyzed. The results of analyses exhibited the increase in strength and improvement in hysteresis behavior of the proposed steel sections under cyclic loading.