The influence of retrofit intervention on vulnerability of masonry buildings from post-earthquake damage data of the last 50 years

The post-earthquake damage data of last 50 years (from Friuli 1976 to Emilia 2012) recently released by the Italian Department of Civil Protection through the online platform Da.D.O. are used in this paper to derive vulnerability curves for the Italian residential building stock. 9 Seismic events of national interest (Friuli 1976; Irpinia 1980; Abruzzo 1984; Umbria-Marche 1997; Pollino 1998; Molise 2002; Emilia 2003; L'Aquila 2009; Emilia 2012) have been considered. Macro-seismic intensity values for each Municipality are evaluated from Macro-seismic database relative to each event (Rovida et al., 2016).Census data relative to locations with Macro-seismic intensities less than 4, resulting undamaged according to the European Macro-seismic Scale EMS-98 (Grünthal, 1998) classification, are used in combination with post-earthquake data in order to avoid any bias in fitting procedures. Vulnerability curves are derived considering Macro-seismic intensity values and observed damage only for vertical structures. Different structural typologies have been considered as a function of structural typologies (seismic and gravitational) and the presence of retrofit interventions and the comparison between the curves is used to prove their effectiveness.