GNGTS 2016 - Atti del 35° Convegno Nazionale

GNGTS 2016 S essione 2.2 413 The geological model of the alluvial valley was defined according to Bozzano et al. , 2016 and it was integrated by a geophysical dataset available from field surveys in order to provide a high-resolution engineering-geological model of the valley. Mechanical and dynamic properties were attributed to each lithotechnical unit according to literature data (Bozzano et al. ., 2016 and references therein). To evaluate the progressive influence of the complex of buildings on the free field local seismic response of the valley, a temporal development of the urban complex has been modelled. The dynamic characteristics of the buildings located in the case study area have been deducted through the CESAR-LCPC code. All the buildings were modelled considering their super-structure, i.e. columns and beams, and assuming the concentrated masses and stiffness in 2D. The so modelled buildings were matched with the engineering- geological 2D models creating some coupled models. More in particular, a series of full 2D time-domain numerical models of the geological cross sections have been prepared through the CESAR-LCPC code assuming two different conditions, the first is a free field condition and the following is Site-City Interaction (SCI) condition. The numerical results were analysed in terms of propagated wave-field along the sections and amplification functions from the point of view of the heterogeneous soil. The amplification function A(f) (Borcherdt, 1994) was obtained considering the spectral ratio between the numerical output in the valley receivers and the input recorded on the outcropping seismic bedrock. Preliminary results show that the presence of buildings induces significant changes of the physical parameters in the areas close to the buildings and may significantly perturbate the local seismic response expected in free field conditions. References Bard P.Y., Chazelas J.L., Guéguen P., Kham M., Semblat J.F.; 2005: Site–city interaction. Chapter 5 of the book ‘‘assessing and managing earthquake risk (geo-scientific and engineering knowledge for earthquake risk mitigation: developments, tools and techniques)’’, Oliveira CS, Roca A, Goula X Editors, Springer (new book series on geotechnical, geological and earthquake engineering). Hardcover. ISBN: 1-4020-3524-1:91-114. Bozzano F., Lenti L., Marra F., Martino S., PacielloA., Scarascia Mugnozza G. and Varone C.; 2016: Seismic response of the geologically complex alluvial valley at the “Europarco Business Park” (Rome – Italy) through instrumental records and numerical modelling. Italian Journal of Engineering Geology and Environment, 1 , pp. 37-55. Gueguen P., Bard P.Y.; 2005: Soil–structure and soil–structure–soil interaction: experimental evidence at the Volvi test site. J Earthq Eng 9 (5):657–693. Kham, M., Semblat J.F., Bard P.Y. and Dangla P.; 2006: Seismic site-city interaction: main governing phenomena through simplified numerical models. Bull. Seismol. Soc. Am., 96 , no. 5, pp. 1934–1951. Martino, S., Lenti, L., Gélis, C., Giacomi, A.C., Santili d’Avila, M.P., Bonilla, L.F., Bozzano, F., and Semblat, J.F.; 2015: Influence of lateral heterogeneities on strong-motion shear strains: simulation in the Historical Center of Rome. Bull. Seismol. Soc. Am., 105 , no. 5 (in press) Semblat J.F., Kham M. and Bard P.Y,; 2008: Seismic-Wave Propagation in Alluvial Basins and Influence of Site-City Interaction . Bull. Seismol. Soc. Am., 98 , no. 6, pp. 2665-2678. On liquefaction Microzoning strategy at level 2/3 for improving resilience of urban areas G. Vessia 1,2 , M.L. Rainone 1 , A. Di Domenica 1 , A. Pizzi 1 , S. Giallini 1,3 , A. Pagliaroli 1 , M. Moscatelli 3 , A. Di Giovanni 1 , F. Solari 1 1 Dipartimento di Ingegneria e Geologia, Università degli Studi ‘‘G. d’Annunzio’’ di Chieti-Pescara, Italy 2 Istituto di Ricerca per la Protezione Idrogeologica, IRPI, Consiglio Nazionale delle Ricerche CNR, Bari, Italy 3 Istituto di Geologia Ambientale e Geoingegneria, IGAG, Consiglio Nazionale delle Ricerche CNR, Roma, Italy Introduction. Microzoning studies have been developed and conceived as a profitable strategy to tackle seismic hazard estimation at local scale. Microzoning activity in Italy has recently been promoted according to three working levels: level 1 – geological susceptibility;