Seismic performance of GFRP-rubberized concrete-steel hybrid solid columns

Abstract

The application of structured rubberized concrete offers an effective solution for recycling rubber tires. This paper proposes a novel GFRP-rubberized concrete-steel hybrid solid columns (GRSRC), which combines rubberized concrete with circular FRP-concrete-steel double-skin tubular columns (DSTCs). Quasi-static tests were carried out on 7 GRSRC specimens to investigate the influence of rubber contents, steel tube diameters, and axial load ratios on their seismic performance. The test results indicate that the GRSRC has excellent ductility, lateral displacement capacity, and energy dissipation capacity. The GRSRC exhibits slow strength degradation at large lateral displacements due to the double-tube confinement effect. Using rubberized concrete with a rubber content of 20% as a replacement for ordinary concrete has little impact on the seismic performance of the specimens. When the rubber content reaches 40%, the seismic performance decreases significantly. Furthermore, its lateral load-bearing capacity, energy dissipation capacity, and deformation capacity are also reduced with the decreasing diameter of the steel tube, resulting in brittle damage. Increasing the axial load ratio enhances the stiffness, lateral load-bearing capacity, and energy dissipation capacity but may reduce ductility, deformation capacity, and hysteretic performance. Finally, a simplified model of GRSRC restoring force is established and validated, providing a theoretical basis for practical engineering applications.