This thesis analyzes the structural behavior of reinforced concrete beam-column joints that have been repaired or strengthened using composite materials, specifically CFRP. The focus is on the analysis of experimental data from the ILISBAR project, conducted at the EMGCU laboratory of Gustave Eiffel University. In particular, three specimens subjected to cyclic loading are examined: a traditional reinforced concrete specimen, a damaged and subsequently repaired specimen, and a specimen strengthened with FRP from the outset. The results highlight that the use of FRP materials significantly improves the ductility and energy dissipation capacity of the structural elements. Subsequently, a finite element numerical model was developed to simulate the structural behavior from a theoretical standpoint.