Ultimate strength of rectangular CFT column

This paper presents the analytical method for predicting the ultimate strength of rectangular concrete filled tube column section. It is based on the concept that the concrete core develops its ultimate strength as a reference for determining the corresponding steel forces. The concrete forces for a rectangular section has already been presented at the ISEC-01 conference. Hence, this paper describes only the method of determining the steel forces to be added to the concrete forces for the ultimate strength of rectangular CFT column. Variables considered are concrete strain, ultimate concrete stress, steel yield strength, length and width of the rectangular concrete core, wall thickness of steel tube and position of the column capacity axis. At ultimate condition of stress/strain, the,resulting steel stress volumes on the CFT shell area are thus determined. Comparison of results with published data showed divergent values of the customary methods from this analytical method.