Guidelines for restoration and improvement of historical centers in seismic regions: the Umbria experience

A methodology ofinvestigation and diagnosis ofthe built patrimony ofhistoric centres in seismic areas ofItaly is proposed ; the aim is to collect an extensive knowledge on the structural typologies and behaviour ofhistoric masonry buildings for the prevention anel/or repair of damages caused by earthquakes. Small historic centres or residential buildings in larger centres have been for long time considered as "minor architectures", but they are meaningful testimonies of the Italian cultural heritage. The results of the investigation also allowed a criticaI review ofthe reliability ofthe analytical models and ofthe effectiveness ofthe repair techniques, applied in the past decades. The guidelines emerging from the results of an extensive research are presented. A "minimal" investigation program, which can support the designers in their projects and appropriate mathematical models to study the vulnerability of the structures is suggested.