A NOVEL SEISMIC VULNERABILITY ASSESSMENT OF MASONRY FAÇADES: FRAMING AND VALIDATION ON CALDAROLA CASE STUDY AFTER 2016 CENTRAL ITALY EARTHQUAKE

An important portion of the historical built environment, which is characterized by un-reinforced masonry, is particularly vulnerable to collapse in case of earthquakes, as demonstrated by recent events. Strategies to target the facades of the most vulnerable buildings need to be tailored for retrofitting and emergency planning. In this research, a novel expeditious vulnerability assessment method, particularly suitable for historical masonry aggregates, is proposed. The method allows assessing the vulnerability index based on information available from external surveys on the building, thus facilitating and speeding up the investigation. If other more precise information (e.g., curbs and tie rods effectiveness) is available, the vulnerability estimation can be improved. The method focuses on out-of-plane mechanisms of the facade, which cause debris to fall on adjacent streets, impeding emergency response. The expeditious method is tailored starting from analytical methods applied on a large sample of historical buildings hit by earthquakes, and validated by means of comparison with kinematic analysis and observed damage state on a relevant case study, Caldarola (Macerata, Central Italy, which was struck by the earthquake in 2016). Results show a good agreement between the proposed method, the kinematic analysis, and the observed damage state of the considered case study, with 75% and 87.5% correspondence, and the method is especially precise for evaluating highly damaged facades.