Axial compression behavior of core-steel tube with T-shaped flanges reinforced concrete column

A novel core-steel tube with T-shaped flanges reinforced concrete (CSTRC) column is proposed. The steel skeleton of CSTRC columns consists of a core-steel tube with T-shaped steel welded around the steel tube. Ten CSTRC column specimens and one contrast specimen without core-steel tube are tested to examine their axial compression behavior. The effects of the cross-section form of core-steel tubes, the steel flange width, steel flange thickness, steel web height, and volume ratio of stirrups on the failure mode and bearing capacity of CSTRC column are also methodically investigated. Furthermore, finite element models are developed to conduct parametric studies to determine how the strength of both the concrete and the steel skeleton affects the bearing capacity and ductility. Finally, a calculation formula to predict the axial compression bearing capacity of CSTRC columns is established. The test results reveal that: (1) compared with the contrast column, all CSTRC columns exhibit good bearing capacity, with a better deformation regime; (2) the cross-section form of core-steel tubes has little influence on the bearing capacity of CSTRC columns, but demonstrates great impact on its ductility. Additionally, growing the width and thickness of the steel shape flange and lessening the stirrup spacing enhances the ductility of CSTRC columns; (3) increasing the strength of both the concrete and the steel skeleton improves the bearing capacity of columns, but decreases the ductility; (4) the prediction results calculated by the proposed approach agree well with the experimental results, which confirms the suitable accuracy of the proposed method. A novel core-steel tube with T-shaped flanges reinforced concrete (CSTRC) column, in which the core-steel tube includes a round steel tube and square steel tube, is proposed. The steel skeleton of newly designed CSTRC columns consists of a core-steel tube with T-shaped steel welded around the steel tube. Ten CSTRC column specimens and one contrast specimen without core-steel tube are tested to examine their axial compression behavior. The effects of the cross-section form of core-steel tubes, the steel flange width, steel flange thickness, steel web height, and volume ratio of stirrups on the failure mode and bearing capacity of CSTRC column are also methodically investigated. The test results reveal that: (1) compared with the contrast column, all CSTRC columns exhibit good bearing capacity, with a better deformation reg