Design of RC Columns Using Glass FRP Reinforcement

Current guidelines do not cover the subject of the fiber-reinforced polymer (FRP) reinforced concrete (RC) members subjected to simultaneous flexural and axial loads. The obvious implication is that, presently, RC columns cannot be designed with FRP longitudinal bars and ties. This paper suggests the consideration of this type of application of glass FRP (GFRP) reinforcement for the next revision of guidelines by (1) showing the theoretical approach at the basis of the behavior of GFRP-RC members subject to simultaneous flexural and axial loads; (2) providing revised design and analysis provisions for GFRP-RC columns similar to those in practice for steel-RC columns; (3) showing how interaction diagrams can be developed for both rectangular and circular cross sections; (4) explaining the rationale for a new formulation of the strength reduction factor for simultaneous flexural and axial resistance that is consistent with current guidelines, and; (5) reformulating the shear strength computation. Recognizing the limited availability of experimental data on GFRP-RC column behavior, the design provisions proposed in this paper are not applicable to structures in seismic zones and may be applicable only to buildings of limited size and height. An example of the design of a GFRP-RC square column for a hospital facility concludes the paper.