NONLINEAR ANALYSIS OF CFT SUBJECTED TO COMBINED AXIAL COMPRESSIVE FORCE AND MOMENT

摘要

Proper material constitutive models for concrete-filled tube (CFT) columns subjected to combined axial force and bending moment are proposed and verified by the nonlinear finite element program ABAQUS against experimental data. The cross sections of the CFT columns in the numerical analysis are categorized into three groups, I.e., circular section, square section, and square section stiffened by reinforcing ties. Via the numerical analyses, it is shown that the steel tubes can provide a good confining effect to the concrete core when the axial compressive force is large. The confining effect of square CFT stiffened by reinforcing ties is stronger than that of the same square CFT not stiffened with ties but weaker than that of circular section. When the spacing of reinforcing ties is small, the CFT with square section might possible achieve the same confining effect as that with circular section.