Characterization of design parameters for fiber reinforced polymer composite reinforced concrete systems

TLDR

Fiber‑reinforced polymers are increasingly used in construction, particularly as corrosion‑resistant reinforcement bars in concrete, promising longer service life than steel. This study evaluates three types of glass‑fiber‑reinforced polymer bars and proposes modifications to existing design methods. The analysis shows that current predictive equations overestimate long‑term performance of GFRP bars, risking inadequate strength, deflection, crack width, and bond in reinforced concrete elements.

Abstract

Fiber-reinforced polymers (FRP) are being increasingly used in the construction industry. One application is to use FRP bars as reinforcement in concrete. It is thought that FRP bars do not exhibit the type of expansive corrosion exhibited by steel reinforcing bars; FRP bar reinforcement embedded in concrete will result in longer service-life expectancies. This report presents results from research performed on three types of glass fiber-reinforced polymer (GFRP) reinforcing bars. The results indicate that some current predictive equations for evaluating long-term properties may overestimate actual performance of GFRP reinforcing bars and GFRP-bar reinforced concrete systems. By unconservatively underestimating GFRP characteristics, key design requirements such as strength, deflection, crack width, and bond may not be adequately addressed in the design of GFRP-bar reinforced concrete elements. As such, recommendations are made to modify existing design methodologies.