Deformation capacity of concrete columns reinforced with CFT

The aim of this research is to investigate the applicability of a concrete-filled tubular steel (CFT) as reinforcement for RC-structures, which are requested to have high deformation capacity. Both types of test specimens of the RC-column with CFTs and the RC-column with reinforcing bars have the same dimensions, and are designed so that they could have an equal strength due to the same quantity and/or strength of reinforcement. Two types of steel-tubes whose dimensions are phi 42.7 X2.3 mm and phi 27.2 X 2.3 mm are also used for the CFTs. An axially constant load and a horizontally cyclic load are applied to the column top. It is found that the RC-column with CFTs is excellent at the deformation and energy absorption capacity compared with the RC-column with reinforcing bars, and that there is no effect of the ratio of diameter to thickness of steel-tubes on the behavior of the columns.