Structural reinforced concrete (RC) elements incorporating glass fiber-reinforced polymer (GFRP) bars have been claimed to exhibit notable deformability under seismic loading. In this research, an attempt has been made to evaluate the influence of replacing steel bars with GFRP bars on the behaviour of RC beam-column joints. To this end, five ½ scale joints were fabricated and examined under cyclic and axial loading. The joints were the same in terms of specimens’ geometry, material properties and test setup while they differed in the number of beams’ steel bars replaced with GFRP bars. Otherwise noted, GFRP-to-steel bars ratio was changed by 0 (reference specimen), 25%, 50%, 75% and 100%. The crack propagation and force–displacement hysteresis curves are presented as the main test outputs. Moreover, seismic parameters namely displacement ductility, absorbed energy, stiffness and equivalent damping ratio are compared and discussed. Overall, the results demonstrated that incorporating GFRP bars by the ratio of less than 50% could enhance cyclic response of joints in terms of ductility, absorbed energy and equivalent damping ratio.

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