EXPERIMENTAL STUDIES ON BEHAVIOR OF EXPANSIVE CONCRETE-FILLED SQUARE STEEL TUBE COLUMNS UNDER ECCENTRICALLY COMPRESSED LOAD

Square expansive concrete-filled steel tubes (ECFT) are a sort of optimization design for concrete-filled steel tubes (CFT) .Tests on 18 eccentrically compressed square ECFT specimens were carried out.The mechanical behavior of the members under eccentrically compressed load was studied.The experimental results indicated that the ultimate strength of eccentrically compressed square ECFT columns with appropriate expansion agent was increased by 3% ～ 12% as compared with that of ordinary CFT columns.Moreover,the influences of the expansion agent, eccentricity ratio and width-thickness ratio on the behavior of eccentrically compressed square ECFT columns were also investigated.The achievements of the paper could be a reference for the design and the theory study of square ECFT members．