Investigation into the behavior of a novel steel section for concrete filled tubular columns under axial and cyclic loadings

Concrete filled steel tube type of construction is becoming increasingly popular in today’s construction practice. Adaptability, economy, installation, elimination of formwork cost and good performance are among the advantages achieved in using this system. The effective parameters on load carrying capacity of CFT columns are the bond between the steel and internal concrete, local buckling strength of steel tube, creep of concrete and loading conditions of column at connections. Considering these effective parameters, a novel section is suggested which can be used for columns of tall buildings and bridges with large spans. The main characteristic of the suggested steel section is internal symmetric stiffeners. In the present study, a comparative investigation into the behavior of this novel section (with circular and octagonal shapes) and the most common used sections of CFT has been carried out under axial and cyclic loading. The results of this study clearly exhibit the high strength and ductility of the suggested novel section under axial and cyclic loading and therefore, its application is strongly recommended in construction practice.