Torsional Behavior of Concrete-Filled Circular Steel Tubes Strengthened with CFRP

In order to study the torsional performance of steel tube concrete after reinforcement with a carbon-fiber-reinforced polymer (CFRP), the mechanical properties of 18 specimens were studied from both experimental and finite element perspectives. The T-θ curve and τ-γ curve of the specimen were measured in the experiment, and the failure mode of the specimen was analyzed. Subsequently, a reasonable finite element model was established using ABAQUS software, and the variation in various parameters surrounding the performance of the specimen was analyzed. Based on the experimental and finite element results, a formula for calculating the bearing capacity of the specimen was established. According to both the experimental and numerical results, the torsional bearing capacity of C-CF-CFRP-ST, defined as the torque endured by the specimen with maximum shear strain, was determined to be 15,000 με, together with its corresponding calculation formula. After the test, it was demonstrated that the main components of the concrete-filled CFRP-steel tube composite material—the steel tube and the concrete—could be used as reusable resources.