FRP STRENGTHENING OF BEAM-COLUMN JOINTS: EXPERIMENTAL VALIDATION AND ANALYTICAL MODELLING

Recent major earthquakes have made clear the role of seismic detailing is in the seismic performance of existing buildings in earthquake-prone areas. However, many older reinforced concrete (RC) structures -especially those built to outdated standards in the Mediterranean area- are highly vulnerable. One of the most critical parts are the beam-column joints (BC joints). Many of these joints, built according to older codes, lack sufficient transverse reinforcement or even have no stirrups, leading to premature brittle failures. Externally bonded FRPs have shown to be very effective in strengthening these joints by improving shear resistance, helping prevent joint failure, and reducing the overall risk to the building. A criticism with many strengthening layouts often used in the practice is that they have high disruption leading to the interruption of the building’s usability. This study deals with the experimental validation of recently proposed FRP strengthening layouts that minimize that level of disruption to the occupants and can be applicable operation from the exterior of the building. The preliminary results of the experimental program are reported and discussed together with a close comparison with the predictions of strength capacity models available in literature.