Retrofitting of beam-column exterior joint with HPFRC jacketing

For RC frames designed before the ’70s it is widely recognized that beam-column joints represent critical regions in presence of seismic loads, so that the joint behaviour influences the response of the whole structural system. Furthermore, a large number of existing buildings need to be strengthened with respect both to vertical and seismic loads. In the present research work the effectiveness in strength- ening existing R/C structures by means of an innovative technique based on the application of a High Performance Fiber Reinforced Concrete jacket is investigated. Analytical evaluations are performed in order to show the increase in strength and ductility provided by the proposed technique. A simple nu- merical model is also used to design an experimental campaign on full scale specimens representing exte- rior beam-column joints subjected to cyclic loads, designed according to the structural details typical of the Italian construction practice of the 60’s-70’s.