Post-seismic effectiveness of the strengthening work carried out with GFRP applied to historical masonry buildings: the case study of the Spoleto Cathedral

The sequence of major earthquakes that has affected Italy in recent decades has required the use of new materials and innovative techniques for the security of damaged buildings. Fibre Reinforced Polymer (FRP) represents a novelty in the field of seismic improvement techniques applicable also to historical masonry structures. The use of composite materials can respect the conservation principles of the monumental buildings. This study describes the effectiveness of the seismic improvement techniques carried out by means of FRP in the Spoleto Chatedral (Italy) after the 1997 Umbria-Marche earthquake. The strengthening work concerned the making safe of damaged vault structures by means of gluing fibreglass bands (GFRP). After 20 years, during the 2016 Amatrice-Norcia earthquake, near Spoleto, the cathedral reinforced with the GFRP bands has not suffered any damage demonstrating the effectiveness of the seismic strengthening techniques.