Effectiveness of externally bonded FRP systems in restoration of RC structures in seismic areas

This study deals with use of externally bonded FRP materials in repair of existing buildings. The first part of the paper concerns results of an experimental program developed by the authors and aimed at evaluating cyclic response of RC specimens previously damaged and then repaired by carbon FRP reinforcements. Test results showed that the adopted reinforcing systems were capable to give repaired specimens a significant increase in strength and deformation capacity with respect to undamaged specimens tested without external reinforcement (control specimens). Besides, a remarkable stiffness degradation of repaired specimens was observed. Therefore, in order to evaluate the influence due to the presence of damaged columns, inelastic dynamic analysis of spatial structures has been performed. Numerical results pointed out a better seismic performance of structures containing repaired elements with respect to corresponding structures consisting of undamaged members.