Seismic Behavior of Exterior GFRP-RC Beam-Column Connections: Analytical Study

Four full-scale specimens were constructed and tested under reversal cyclic loading to study the seismic behavior of exterior glass fiber-reinforced polymer (GFRP)-reinforced concrete (RC) beam-column joints with lateral beams. The test variables were joint shear stress (0.85, 1.0, and 1.1 times the square root of the concrete compressive strength) and type of reinforcement (steel or GFRP). Test results indicated that well-designed exterior GFRP-RC beam-column joints confined with lateral beams exhibit linear behavior with minimum residual damage up to 5% drift ratio. A specialized software was used to construct a finite elements model, capable of simulating hysteresis behavior of reinforced concrete beam-column joints under seismic loading by taking into account the nonlinear behavior of concrete, confinement provided by the internal reinforcement, and the effect of cracks and bond-slip relationship between reinforcing bars and surrounding concrete. The model was used to investigate the effect of joint shear stress, size of lateral beams, reinforcement material, column axial load, and geometrical configuration on the joints' behavior.