Abstarct: Abstract Beam-column connections play a main role in transferring gravity and lateral loads between structural elements. Previous earthquake experiences have shown that reinforced concrete (RC) moment frxames have significant vulnerability due to inadequate non-seismic detailing in the connection region. This study presented an innovative and practical method called joint enlargement for retrofitting corner RC beam-column connections with non-seismic details. The proposed methods enlarged the connection area by using prestressed steel angles in both two-dimensional and three-dimensional spaces. To evaluate the retrofit methods, five beam-column connections, including two control connections and three retrofitted connections, were tested with a constant axial force of 0.16fcAg and a cyclic load with increasing amplitude. All five specimens were compared baxsed on seismic parameters, including ductility factor, energy dissipation, equivalent hysteretic damping, stiffness degradation, crack patterns, and hysteresis curves. The results indicated that the retrofitting methods successfully relocated the plastic hinge to the end of the beam, after the edge of the steel angles. Furthermore, the use of the proposed methods increased the average maximum force in both loading directions and the energy dissipation capacity at a drift of 6% by approximately 22% and 214%, respectively, with respect to the specimen with non-seismic details.