Axial bearing capacity of composite concrete-filled steel tubular columns

In order to study the bearing capacity of composite concrete-filled steel tube(CFST) reinforced by inner steel tube or steel column,the unified theory of CFST is applied to calculate the strength of the composite CFST under axial compression.The performance and mechanism of composite columns under axial compression are analyzed.With consideration of different sections of inner and outer steels,the equivalent hooping coefficient is proposed;then the strength of the composite columns is analyzed.Formula solutions are testified by test results of references.The result shows that the formular of the unified theory is also reasonable for the composite CFST columns,and it is a new simple unfied approach to calculate the axial bearing capacity of composite CFST columns with high accuracy.2 tabs,2 figs,12 refs.