Properties of High-Strength Concrete Filled Steel Tube Columns

High Strength Concrete Filled Steel tubes (CFST) provide a common construction material in China. The purpose of this research was to determine the axial load properties for CFST subjected to concentric and eccentric loading in a series of experiments. The results show that the magnitude of experimentally measured compressive strength increases for the core concrete, due to the confinement from the steel that is proportional to the ratio of the area of steel to the area of concrete. If the slenderness ratio is kept constant the columns bearing capacity and maximum strain decreases as the eccentricity to radius ratio increases. Formulas to estimate the load bearing capacity for short and for slender eccentrically loaded columns were established from the data. The results have been compared statistically to other published results to show that a general linear form of the capacity equation is warranted for High Strength Concrete Filled Steel tubes.