Abstract:
In order to study the reinforcement performance of self-compacting recycled concrete filled steel tubes on reinforced concrete (RC) short columns. With the RC short column's concrete strength, steel tube thickness, replacement ratio of recycled coarse aggregates, number of layers of Carbon Fiber Reinforced Polymer (CFRP) fabric and the cross-sectional diameter of the reinforced component as varying parameters. Conduct axial compression tests on one unreinforced short column and eleven reinforced short columns. Observe the entire process of force-induced failure in the test specimens, obtain the load-displacement curve, and analyze the impact of various changing parameters on the residual bearing capacity, initial axial compressive stiffness, and ductility. Develop an extended analysis using the ABAQUS finite element model. Introduce safety factor and material utilization factor for recycled coarse aggregate, and propose a formula for calculating axial compressive capacity based on limit equilibrium theory. The results indicate that both the ductility and stiffness of the reinforced RC short columns are significantly improved, and the failure modes all exhibit ductile failure. The ultimate stress enhancement factor for reinforced RC short columns ranges from 1.14 to 2.30. The thickness of the steel tube and the number of CFRP layers have a significant effect on enhancing the load-bearing capacity. However, the method of boosting bearing capacity by enlarging the restraint coefficient and diameter has limited effectiveness. An increase in the replacement rate of recycled coarse aggregate in sandwich structures will reduce the bearing capacity. The experimental data aligns well with the finite element simulation data. The extension results indicate that an increase in both the yield strength of steel tubes and the strength of recycled concrete can significantly enhance the bearing capacity, while the change in slenderness ratio has an insignificant impact on the bearing capacity. The average error of the formula for calculating axial compressive capacity based on the limit equilibrium theory is within 5%.