REPAIR AND STRENGTHENING OF HISTORIC MASONRY BUILDINGS IN SEISMIC AREAS

The 1997 Umbria- Marche earthquake offered a unique opportunity to verify the knowledge on seismic response and on retrofitting strategies of historic masonry structures which have been developed during the last twenty years. Severe damages were in fact suffered also by those buildings that had already been, and in some cases were still being, repaired and strengthened-after the effects of the previous 1979 earthquake- according to the most updated expertise in this field, as it is expressed by the national recommendations. The study of the actual efficiency of current techniques for repairing and strengthening historic masonry is particularly dealt with in the paper. To this scope, the authors are carrying out extensive surveys on damaged buildings in order to accurately analyze the observed failure mechanisms. The crucial problems of the structure and materials incompatibility that frequently occurred are particularly taken into account