GNGTS 2013 - Atti del 32° Convegno Nazionale

length. Distribution of infill elements in RC buildings was also surveyed. In the following, main data resulting from the field survey are briefly presented. On the whole, 1327 buildings were surveyed. Among these, 1058 were RC buildings and 265 were masonry buildings, see Fig. 1a. Steel and mixed buildings were present in negligible percentages (only 4 buildings out of 1327). In Fig. 1 the distributions of number of storeys and age of construction among the building population are reported. It is to be noted that in the period ranging from the ‘40-‘50 up to the ‘80-’90 there was the greatest diffusion of the RC Buildings, at the turn of post-war economic development and reconstruction after the 1980 Irpinia earthquake. Moreover, pre- and post-81 buildings respectively represent about the 56 and 44% of the RC building population whose age of construction was determined, which represent the 80% of the total. Remote sensing data. Remote Sensing (RS) techniques provide a wide range of environmental information about landscape and its characteristics, especially in the case of studies concerning urbanized areas, offering significant advantages in terms of cost effectiveness and timeliness in the availability of information over larger areas. In this framework, RS techniques can be a valuable source of information about 3D geometry of buildings with the aim of supporting seismic vulnerability assessment of building stocks. A specific methodology has been implemented and calibrated within the SIMURAI project by the research group of the “Earth Observations and Analyses” laboratory (UTMEA-TER) of the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA) in order to excell 3D buildings parameters using RS data acquired from aerospatial platforms, in particular by means of active LIDAR (LIght Detection And Ranging) technology, which allowed to assess the height and planimetric shape of buildings. A LIDAR airborne RS mission has been planned and carried out in 2007 over the entire municipality of Avellino, acquiring range point clouds data with a density of 4 points for square meter. The 3D geometric parameters of buildings were extensively obtained through a methodology integrating active LIDAR technology, aerophotogrammetry and GIS techniques, as briefly described in the following. The LIDAR data have been processed in order to excell the Digital Surface Model (DSM) and the Digital Terrain Model (DTM); then buildings have been excelled from non-ground points. Subsequently, GIS procedures have been specifically implemented to describe the built-up areas and to store all the data acquired and the information produced in a specific GeoDatabase. The digital cartography at 1:2000 scale of the Municipality of Avellino has been used to overlay vector information about the buildings (especially, their footprint) with LIDAR data. Therefore, combining digital cartography and height values coming from LIDAR, for each building geometric attributes and morphological features have been excelled in a semi- automatic way: area, perimeter, volume, total height of the building and ground altitude beneath itself. In particular, this task has been carried out using the approach proposed by Borfecchia et al. (2010). For further information about LIDAR data acquisition and processing the reader is referred to (Ricci et al. , 2011), where the work carried out by the UTMEA-TER ENEA laboratory is described in detail. Census data. The Italian National Institute of Statistics (Istituto Nazionale di Statistica, ISTAT) survey is a nation-wide census that provides information on citizens, foreign, buildings and dwellings. In particular the “14 th general census of the population and dwellings” (14° Censimento generale della popolazione e delle abitazioni, ISTAT 2001) collected information about 57 millions of citizens, 13 millions of buildings and 27 millions of dwellings. Data about the number of storeys as well as characteristic of residential buildings, and in some cases even those non residential, were collected. This census provides the statistics of buildings, unlike previous census which provided statistics about dwellings, related to number of storeys (one-, two-, -three and (≥four)-storey buildings), age of construction (typically with a decennial-rate) 52 GNGTS 2013 S essione 2.1