The Working Performance and Combined Axial Compressive Strength Theory of the Concrete-filled Steel Tube

Abstract

Studies show that the applicable range of conventional expression for calculating the axial compressive strength of the concrete-filled steel tube (CFST) is limited. In order to resolve this shortcoming, the formula of combined axial compressive strength of the CFST is obtained in the present study based on its axial compression performance. To this end, coordination requirements of radial deformation are refined and relaxed and then the constitutive relation of the specific material element is replaced with generalized Hooke's law. It is found that the combined strength of steel tube at yield is in accordance with the unified theoretical results and experimental results of ultra-high-strength CFST. According to the results obtained, the application range of strength combination of CFST is extended, which provides an important basis for designing the CFST structure.