Nonlinear Analysis of Hybrid GFRP-Steel Reinforced Beam-Column Joints Under Cyclic and Axial Loading

This study investigates the cyclic behavior of reinforced concrete beam–column joints strengthened with hybrid GFRP–steel reinforcement using nonlinear finite element analysis. Six hybrid configurations—defined by varying the percentage of the total longitudinal steel reinforcement area, in the beam, replaced with GFRP bars (0%, 20%, 25%, 33%, 50%, and 100%)—were evaluated in terms of load–displacement hysteresis, stiffness degradation, dissipated energy, and crack development. A multi-criteria decision analysis (MCDA) was employed to quantitatively compare the six configurations. The findings demonstrate the potential of partial GFRP substitution to enhance the seismic performance of reinforced concrete beam–column joints.