EXPERIMENTAL STUDY ON THE BEHAVIOR OF LIGHTWEIGHT AGGREGATE CONCRETE FILLED CIRCULAR STEEL TUBES UNDER AXIAL COMPRESSION

摘要

Based on axially compressive tests of 34 lightweight aggregate concrete filled steel tube (LACFT) stub columns and medium length columns, macroscopic characters of deformation, failure mechanism and failure mode were analyzed. With the comparison of load-strain curves of members with different parameters, the influencing parameters of mechanical properties were studied. In addition, the test results were contrasted with the bearing capacity of normal concrete filled steel tubes (CFT) referring to published data. As a result, confining ratio is found to be a significant parameter to the mechanical properties of LACFT stub column. The larger confining ratio is, the higher ultimate bearing strength and ductility of LACFT stub columns are. Slenderness ratio is another important parameter of LACFT medium length column. The larger slenderness is, the higher bearing strength of LACFT columns have. Furthermore, in the same condition, the ultimate bearing capacity of LACFT stub columns is close to that of CFT stub columns while the ultimate bearing capacity of LACFT medium length columns is higher than that of CFT medium length columns.