Role of the Bar-Concrete Interfacial Properties on the Load Response of GFRP-Reinforced Notched Beams

Replacement of steel bars with GFRP (glass fiber-reinforced polymer) bars in reinforced concrete (RC) members is becoming widespread, especially in structures subjected to aggressive environmental conditions. As for steel-RC members, the structural response of GFRP-RC members is governed by the bar-concrete interfacial properties. GFRP bars can be produced with different surface configurations, resulting in different bar-concrete interfacial properties. The bond properties of GFRP bars are usually evaluated with pull-out tests due to the simplicity of the test setup. However, the state of stress at the bar-concrete interface in pull-out specimens and RC members can be different due to the different cracking and confinement conditions. Therefore, it is important to evaluate whether the interfacial properties obtained from pull-out tests can be used in analytical or numerical models to obtain the structural response of RC members. In this paper, the bar-concrete interfacial cohesive materla law (CML) obtained from pull-out tests of a GFRP bar in a previous study is used in an analytical model to simulate the experimental response of GFRP reinforced notched beams subjected to three-point bending test.