Investigation of the Effectiveness of CFRP Strip Ties as Transverse Reinforcement for GFRP Bar–Reinforced Concrete Columns

Abstract

This paper investigates the effectiveness of carbon fiber–reinforced polymer strips ties (CST) as the transverse reinforcement for normal strength glass fiber–reinforced polymer reinforced concrete (GFRP-RC) square columns. The axial compressive behavior of GFRP-RC columns transversely reinforced with CST has been investigated. In particular, the effectiveness of CST configurations, confinement efficiency, and center-to-center spacing of the CST was investigated. A total of 13 specimens with 200 × 200 mm cross section and 800 mm height were tested until failure. One specimen was longitudinally reinforced with steel bars and transversely reinforced with square steel ties as a control specimen (S-RC). The remaining 12 specimens were longitudinally reinforced with GFRP bars and transversely reinforced by either square (S), or square overlapping square (SS), or square overlapping circular (SC) configurations of the CST. Test results showed that the specimens with SC configuration of CST achieved higher confinement efficiency and deformability than the specimens with S and SS configurations of the CST. In addition, the increases in the confinement efficiency and deformability for the reduction of the spacing of the CST are more pronounced for the specimens with SC configuration of the CST compared to the specimens with either S or SS configuration of the CST.