Seismic Behavior of High-Strength Concrete Circular Columns Reinforced with Glass Fiber-Reinforced Polymer Bars

The linear elastic behavior of fiber-reinforced polymer (FRP) reinforcement makes it controversial to implement in seismic-resistant reinforced concrete (RC) structures. More concerns could be raised when such reinforcement is associated with high-strength concrete (HSC). Columns in multi-story buildings or bridges are common examples of structural members constructed using HSC. To date, all available research data on glass FRP (GFRP)-RC columns have shown that they have a maximum limit of concrete compressive strength equal to approximately 55 MPa (8000 psi). The results of five full-scale column-footing specimens are presented to study the seismic response of GFRP-RC columns, highlighting the effect of concrete compressive strength alongside other factors such as spiral pitch and axial load. It is concluded that when properly confined, GFRP-reinforced HSC circular columns can exhibit a stable seismic response with sufficient deformability. Moreover, several confinement and performance indexes were adjusted and evaluated to introduce an informative relationship for the design of GFRP-RC columns.