Post-earthquake reconstruction of residential buildings in historical centers: damage indices of structural aggregates

The post-earthquake reconstruction process of historical centers discloses several issues due to the complexity of the built heritage, typically consisting of Building Aggregates (BA). These are characterized by structures deriving from progressive volume increases that, due to partially effective connections, can interact under seismic actions. Therefore, the repair and reconstruction work after seismic event, the conservation of the architectural values and the improvement of seismic and energy performances must rely on a deeper knowledge of the BA seismic behavior and on an unitary design approach. This paper presents an analysis of the damage caused by the 2009 earthquake to the buildings of the historical centers in the Abruzzo Region, with particular interest to the BA considered as a single structural block. A new perspective of the damage on structural and non-structural components, detected by means of the AeDES form, a first level survey form for post-earthquake damage and usability assessment, is proposed. The data related to the building damage are converted into an equivalent global building damage associated to the BA using conversion metrics found in the literature. Finally, some considerations are provided to evaluate the global building damage, necessary to the development of a comprehensive damage state.