Bond-slip constitutive model for glass fiber-reinforcedpolymer rebars in ultrahigh-performance concrete

Abstract

To investigate the bond performance of glass fiber-reinforced polymer (GFRP) rebar and ultrahigh-performance concrete (UHPC), the influence of factors such as fiber-reinforced polymer (FRP) rebar diameter, relative embedment length, relative cover depth, UHPC compression strength, FRP rebar surface type, and test method for GFRP bond strength is systematically analyzed based on experimental data on 153 pullout tests and 42 beam tests. Using regression analysis and prediction interval, calculation formulas for bond strength and development length are proposed for GFRP rebars in UHPC. Available bond-slip constitutive models for FRP rebars in existing concrete are analyzed and compared, and equations for the bond-slip model of helically wrapped GFRP rebars in UHPC are proposed based on the Cosenza-Manfredi-Realfonzo model. The above formulas agree well with the test results and provide a basis for engineering design and follow-up research.