The challenges of GFRP RC beam design for limit states

Glass fiber reinforced polymer (GFRP) bars are used ever more frequently in concrete construction due to their non‐corrosive and anti‐magnetic properties. Their research over the past decades focused on fundamental questions, such as the design aspects of beams under flexural loads. GFRP bars are brittle, have lower stiffness, and have different bond behavior than traditional steel reinforcement. As a result, the preferred failure mode shifts to concrete crushing, which provides slightly higher ductility than bar rupture. The lower stiffness, however, results in larger deformations, leading to serviceability limit states governing the design, making over‐reinforced cross‐sections not just a preference but a necessity. The review offers a critical synthesis of existing research and a comparative analysis of design guidelines for GFRP‐reinforced concrete beams, explaining the underlying phenomena that underpin the recommendations. Research directions are also outlined, along with a practical agenda that identifies the most urgent research needs.