Investigation on Glass Fiber-Reinforced Polymer Bars in Concrete Beams

The use of glass fiber-reinforced polymer (GFRP) bars is an innovative approach to replace traditional reinforcement of steel into concrete structures. GFRP bars provide notable benefits like corrosion resistance, electromagnetic neutrality, higher tensile stress by weight ratio, sustainability, and cost-effective construction reducing maintenance cost. However, challenges like brittleness, reduced ductility, and lower elastic modulus limit their practical applications. This research examines the flexural behavior of GFRP-reinforced concrete beams using experimental and numerical methods. Nonlinear finite element analysis (FEM) was performed in ABAQUS, employing a three-dimensional deformable model, concrete damage plasticity (CDP) theory, and detailed material properties for concrete, steel and GFRP. Four-point flexural load conditions were simulated, and mesh sensitive analysis was conducted to ensure model accuracy. Experimental results demonstrated that GFRP-reinforced beams had higher load-bearing capability, but wider cracks and larger deflections compared to steel-reinforced beams. Failure of flexural members primarily due to concrete crushing was observed. Numerical simulations closely exhibited experimental load deflection performance, stress distributions, and failure patterns with accuracy variation of ~10%–16%. This study highlights the potential of FEM for correctly simulating the performance of GFRP-reinforced concrete beams and comparing the numerical outcomes with experimental studies. It was observed that GFRP-reinforced beams had 20% more load-carrying capacity compared to steel-reinforced beams based on grade of concrete and size of reinforcement. Deflection values for GFRP-reinforced beams were higher compared to steel-reinforced beam leading to requirements for serviceability considerations. The outcome of the study exhibited the potential of GFRP as a superior reinforcing material for specific applications.