Behavior of Full-Scale GFRP Reinforced Concrete Columns under Pure Axial Load

Glass fiber-reinforced polymer (GFRP) bars are emerging as a valuable option as internal reinforcement for concrete structures, particularly when corrosion resistance or electromagnetic transparency is sought. GFRP bars, however, are typically not allowed as compression reinforcement in current design guidelines. An experimental campaign on full-scale GFRP reinforced concrete (RC) columns under pure axial load was undertaken using specimens with a 24 x 24 in. (0.61 x 0.61 m) square cross section. The study was conducted to investigate whether the compressive behavior of longitudinal GFRP bars impacts the column performance, and to understand the contribution of GFRP ties to the confinement of the concrete core, and to prevent instability of the longitudinal reinforcement. The results showed that the GFRP RC specimens behaved similarly to the steel RC counterpart, while the spacing of the ties strongly influenced the failure mode.