Design and Detailing of Glass Fiber-Reinforced Polymer-Reinforced Concrete Beams According to ACI CODE-440.11-22

This paper aims to analyze practical considerations in the design of glass fiber-reinforced polymer-reinforced concrete (GFRP-RC) beams based on the newly adopted ACI CODE-440.11-22, addressing strength, serviceability, and detailing criteria. A beam example was taken from the ACI Reinforced Concrete Design Handbook and redesigned using GFRP bars and stirrups to analyze the effect of changing the reinforcement type. In the first phase, the beam was designed as an over-reinforced member with high-modulus (E-f = 60,000 MPa) and low-modulus (E-f = 44,815 MPa) GFRP bars. In the second phase, a parametric study was carried out to analyze the impact of changing key design parameters-namely, bond factor k(b), concrete compressive strength f(c)', and the maximum deflection limit. GFRP-RC beams require more reinforcement area compared to conventional steel-RC, which may result in bar congestion. Current Code provisions related to detailing in particular are based on conservative assumptions due to a lack of experimentation and greatly penalize the design of GFRP-RC beams. The current Code provisions for development length, bar spacing, skin reinforcement, and stress at service make GFRP-RC design challenging.