BEHAVIOUR OF SPECIAL-SHAPED CONCRETE-FILLED STEEL TUBULAR STUB COLUMNS UNDER AXIAL COMPRESSION

The finite element analysis ( FEA) models for 5 special-shaped ( triangular section，fan-section，Dsection， 1 /4 circular section and semicircular section) concrete-filled steel tubular stub columns with the same perimeter of cross-section under axial compression are developed using ABAQUS software and the corresponding 6 group tests are conducted for comparison． The predicted load versus strain relationship curves and failure modes are in good agreement with the measured results． The FEA models are then used to analyze the interaction between the concrete and the steel tube during the whole loading process． And then，the main parameters influencing the bearing capacity and deformation such as section shape，steel tube wall thickness，steel tube yield strength，concrete compression strength are investigated． The results show the typical failure modes of these stub columns were the outward bulge at about mid-height，the section shape，the steel tube wall thickness and the concrete compression strength have obvious effects on their mechanical behavior，while the steel tube yield strength has slight effect on their mechanical behavior．