GNGTS 2017 - 36° Convegno Nazionale

GNGTS 2017 S essione 2.2 369 riduzione dell’informazione riguardo la presenza di orizzonti, quindi di superfici limite, interni alla formazione geologica con parametri anche molto diversi tra loro, l’uso dei Tipi_Geologico- Tecnici per estrapolare dati puntuali all’intera MOPS, ricostruzione del modello di sottosuolo e parametrizzazione dei corpi geologici nella modellazione 2D sulla base delle poche misure disponibili, combinazione dei risultati della modellazione 2D con quella 1D, ecc. Bibliografia Autori Vari, 2011: Contributi per l’aggiornamento degli ‘‘Indirizzi e criteri per la microzonazione sismica’’, Ingegneria sismica, 28, 2, Patron editore Bologna, Italy, (in Italian) available on line in the website http://www. protezionecivile.gov.it/resources/cms/documents/aggiornamento_indirizzi_microzonazione_sismica.pdf GruppodiLavorosullaMicrozonazioneSismica.2008.Indirizziecriteriperlamicrozonazionesismica.Conferenzadelle Regioni e delle Province autonome – Dipartimento della Protezione Civile, Roma, 3 vol. e DVD, Gruppo di Lavoro sullaMicrozonazione Sismica dell’AreaAquilana. 2010:Microzonazione sismica per la ricostruzione dell’area aquilana. Regione Abruzzo, Dipartimento della Protezione Civile, pp 796 (3 VV e dvd) Issues in the estimation of the dynamical properties of Catania downtown area buildings S. Imposa, F. Panzera, G. Lombardo, S. Grassi Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università degli Studi, Catania, Italy Introduction. Catania is one of the Italian cities having a high seismic hazard. Several studies (Azzaro and Barbano, 2000; Panzera et al. , 2011) show that the seismic history of this area is characterized by large events (1169, 1542, 1693) having a moment magnitude ranging from 6.2 and to 7.3 (Rovida et al. , 2016 ), and enhancement of seismic effects was usually observed as a consequence of local geo-lithologic features. This area was therefore selected to conduct a field experiment aiming to estimate the buildings fundamental period, taking into account their technical features. Simplified methods usually estimate the fundamental frequency of a building by postulating it as a function of its geometry and its total height. In recent years, experimental techniques using either earthquake or ambient noise signals have been proposed to evaluate the dynamic parameters of buildings (Parolai et al. , 2005; Gallipoli et al. , 2008). In the urban area of Catania, a preliminary evaluation of the vulnerability and a few estimates of the fundamental period of buildings, were carried out by Faccioli et al. (1999), Panzera et al. (2013) and Imposa et al. (2017). In this frame, the University of Catania has promoted and supported surveys aiming at evaluating the dynamic features of the buildings making up its assets (Fig. 1). Therefore, contributing to evaluate and reduce the vulnerability of all the University building heritage. Most of the investigated buildings are erected in the Catania downtown, therefore emphasizing their structural complexity (masonry building with the presence of reinforced concrete elements), irregular plan shape and the presence of adjacent structures. The present study refers to the suitability of ambient noise records, processed through the standard spectral noise ratio (SSNR) methods, to define the dynamic properties of masonry buildings in such complex situation. Although, such a technique was already successfully used by several authors in many areas (Gallipoli et al. , 2008) and these kind of studies are important in investigating possible soil-structure resonance effects, some attention should be paid in the interpretation of results.