Simplified survey form of unreinforced masonry buildings calibrated on data from the 2009 L’Aquila earthquake

The 2009 L’Aquila earthquake in southern Italy affected a rather large number of buildings, which experienced macroseismic intensities between V and IX on the Mercalli–Cancani–Sieberg scale. Almost sixty thousand unreinforced masonry constructions were officially inspected and almost half of them ended up losing their usability status temporarily, partially or completely, where the term usability refers to the suitability of a building for habitation or occupancy after a seismic event. A fairly detailed damage and usability form was compiled thanks to the work of a large number of volunteers. However, when pre-event surveys are carried out, data collection needs to be confined to the most relevant information in order to save time and manpower. The main aim of this article is, thus, the definition of a simplified form for pre-earthquake territorial-scale surveys of buildings, one containing fewer usability parameters and categories than the form compiled after the earthquake in L’Aquila. Analysis shows similar usability for buildings with more than two storeys above ground, those with construction timespans after 1962, and structural types with a specific combination of vertical and horizontal structures. Therefore, a simplified tool is recommended, one with just three categories for number of storeys instead of the thirteen in the current form, five construction timespan categories instead of eight, four structural classes instead of the current thirty. Other parameters, such as the presence of isolated columns or of mixed structures, have been removed altogether.