Axial compression bearing capacity of steel reinforced concrete rectangular columns confined by carbon fiber reinforced polymer

Twenty-nine specimens were conducted to the axial compression experiment, in order to study the axial compression performance of steel reinforced concrete rectangular columns confined by carbon fiber reinforced polymer (CFRP). Six parameters were considered, which included reinforcement ratio, preload level, corner radius and aspect ratio of cross sections, as well as amount and scheme of CFRP. Results indicated that the confined columns all failed in the fracture of CFRP when the core concrete crushed. With the increasing preload level, both the effective tensile strain of CFRP and the bearing capacity of confined columns decreased gradually. With the increasing corner radius and decreasing aspect ratio, the circumferential strain of CFRP got higher value and more uniform distribution. As increasing amount of CFRP, the constraint mode of the column changed from weak constraint to strong constraint, and the utilization of CFRP decreased. When the width and spacing of the strips decreased, the increment of bearing capacity increased with the same amount of CFRP. Finally, considering various parameters, the boundary value for determining the strong and weak modes was proposed. The formulation of the axial bearing capacity of confined steel reinforced rectangular columns was set up by superposition method. Copyright ©2022 Journal of Zhejiang University (Engineering Science). All rights reserved.