METHOD OF CALCULATING THE FLEXURAL STRENGTH OF FRP REINFORCED CONCRETE T-SHAPED AND RECTANGULAR BEAMS

To establish a simplified method of calculating the flexural strength of concrete T-shaped and rectangular beams reinforced by fiber-reinforced polymer (FRP) bars, the effective FRP reinforcement ratio ρ_ef and the corresponding balanced reinforcement ratio ρ_{ef, b} were firstly derived from cross-section analyses under balanced failure. In conjunction with a statistical analysis of the experimental results of 257 FRP reinforced concrete (RC) beams, the transition region, where tensile failure and compressive failure were possible, was revised (ρ_{ef, b} <ρ_ef ≤1.5ρ_{ef, b}). A numerical sectional analysis of tension-controlled sections was used for a detailed parametric study of a total of 25 344 sections. Based on a multiple regression analysis of the numerical results, simplified equations were developed for the flexural strength of tension-controlled sections. Besides, design equations were presented for the flexural strength of compression-controlled sections based on the fundamentals of the equilibrium of forces and the compatibility of strains. An experimental database of 257 beams was established and used to verify the accuracy of the proposed approach.