Title: Effect of Weathering Exposure Time on the Flexural Behavior of FRP Strengthened RC Beams

Author(s): Haitham A. Ibrahim, Mohamed F. M. Fahmy, and Seyed Saman Khedmatgozar Dolati

Publication: Symposium Paper

Volume: 360

Issue:

Appears on pages(s): 771-790

Keywords: Reinforced concrete beam, FRP, intermediate crack debonding, finite elements, deterioration, bond strength

DOI: 10.14359/51740662

Date: 3/1/2024

Abstract:
This study numerically investigates the long-term effectiveness of using externally bonded fiber-reinforced polymer (FRP) plates as a strengthening technique for reinforced concrete (RC) beams. A two-dimensional finite element model (FEM) that can accurately predict the flexural behavior of FRP strengthened RC beams, is developed. Weathering exposure time of 0.0, 15.5, 35, and 75 years were considered. In total, 28 different concrete beams were modelled using the developed FEM. The results show that prolonged exposure to natural weathering can cause premature FRP debonding, even before reaching the yielding load. The ultimate load capacity, midspan deflection, and ductility of strengthened RC beams can be reduced by up to 38%, 62%, and 100%, respectively. In addition, the findings raised concerns about the applicability of the ACI 440.2R-17 provisions for calculating the design flexural strength of FRP strengthened RC beams with prolonged exposure to natural weathering. To ensure a safe design for strengthened beams with FRP debonding or concrete crushing failure modes, this paper recommends an additional reduction factor ranging from 0.8 to 0.9. Furthermore, periodic inspection using non-destructive testing and FRP anchorage system are highly recommended for both existing and new applications of FRP in structures.