GNGTS 2021 - Atti del 39° Convegno Nazionale

GNGTS 2021 S essione 2.2 352 Class Age of construction Class Age of construction URM-1 Ancient Build., built before 1937 in non-seismic zones or between 1908 and 1937 in zone hit b earth RC-1 Built before 1939 URM-2 Improved Ancient Build., are Ancient Build. but subjected to retrofit interventions RC-2 Built between 1939- 1970 URM-3 Modern Build., built after 1937 in non-seismic zones, or before 1937 in zones declared seismic between 1908-1937 RC-3 Built from 1971 up to the introduction of seismic Codes for the zone hit by earth URM-4 Semi-modern Build, built before 1937 but after the year of emanation of Seismic Codes for the zones hit by earth between 1908-1937 RC-4 Built according to modern seismic codes URM-5 No Code-conforming Build., built after 1937 or between 1908 and 1937 for zones hit by earth Tab. 1 - Classes of URM and RC buildings Definition of ‘district’ fragility curves Typological fragility curves defined in the previous Section are referred to a single building class and represent the basis for developing ‘district’ fragility curves. In fact, to represent the global seismic vulnerability of a specific urban district, fragility curves must be particularized as a function of i ) typological building classes and ii ) number of buildings for each class present in the district. Thus, the district fragility curves can be considered as mean-representative of the vulnerability level of a specific area. With the term ‘district’ is here intended a more or less wide area which contains a subset of buildings having similar characteristics, such that they can be associated to one of the nine typological classes defined in Tab. 1. Fig. 1 - Typological fragility curves for Italian URM buildings