Concrete beams reinforced with glass-fiber reinforced polymer (GFRP) bars exhibit large deflections in comparison with steel-reinforced concrete beams because of the low modulus of elasticity of GFRP bars. This paper proposes new equations for estimating the effective moment of inertia of FRP-reinforced concrete beams on the basis of the genetic algorithm and experimental results. Genetic algorithm is used to optimize the error function between experimental and analytical responses. In the experimental part of the study, nine beam specimens were manufactured and tested. In addition, the results of 55 beam specimens tested by other researchers were also used. The effects of elastic modulus of FRP bars, reinforcement ratio, and the level of loading on the effective moment of inertia are taken into account. The proposed equations are compared with different code provisions and previous models for predicting the deflection of FRP-reinforced concrete beams. The values calculated using the proposed equations are also compared with different test results. The experimental results correlated well with the values predicted using the proposed equations, especially in the cases of high reinforcement ratios and high levels of loading.

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