Abstarct: The beam–column joints in reinforced concrete structures are among the most important structural elements for flexural frxame behaviour. In most of the existing reinforced concrete connections in Iran and some other countries, common weaknesses are observed during earthquakes, such as the absence of column confinement in this area, inadequate provision of necessary positive beam reinforcement in the connection, failure to maintain the spacing of longitudinal reinforcement which leads to a lack of concrete cohesion with these reinforcements (concrete spalling), failure to adhere to the maximum steel percentage in concrete, etc. Various methods exist to strengthen such connections, one of the most practical techniques being the enlargement of the connection area using steel angles. Laboratory studies are generally costly and time-consuming due to limited laboratory facilities. the finite element method is one of the approaches used by many researchers to examine the influential parameters on connection behavior. However, given the complexity of stress in the connection area and effects such as continuity and concrete cracking, finite element analyses typically do not provide engineers with a satisfactory practical understanding of the behavior. The approach of this research is slightly different from other research, because instead of using a corner, a u channel with a specified cut length and welded together is used, which is cut and welded in its wings using pipes that are cut and welded to pass high-strength grade 16 bolts that are installed and prestressed at the connection. These devices are designed to improve the performance of beam-column joint strengthening and reinforcement. For this purpose, an initial mold was constructed using a 2 mm thick plate, grade 4 angles, and grade 4 straps to create a half-scale frxame. Then, using this mold, a reinforced concrete flexural frxame was cast in three stages (foundation, column, and beam), simulating typical conditions of concrete building construction. Three concrete frxame specimens were prepared: the first with a seismic beam-column joint (continuously tied stirrups in the column joint area) and the second and third as non-seismic frxames (without column stirrups in the joint area). In the structural laboratory, the first two specimens were tested under cyclic loading in the usual manner, while the third specimen was tested using the strengthening devices. The comparison of observational and numerical results showed that the strengthening method effectively enhanced the overall and specific behaviour of the concrete frxame. The results indicated that, in addition to eliminating shear cracks in the strengthening area (beam-column joint), no cracks appeared at the construction joint. This suggests that the installation of the strengthening devices created an integrated concrete structure for the column and beam, as if the concrete for the beam and column had been cast simultaneously.