GNGTS 2018 - 37° Convegno Nazionale

GNGTS 2018 S essione 2.2 415 The 1D site response analyses have been performed using three free field natural accelerograms at the bedrock, specific of the seismicity of central Italy, which were recorded by the Italian Accelerometric Netwotk (RAN): (i) 6 April 2009 (Mw: 6.1) L’Aquila earthquake recorded at the AQG station; (ii) 30 October 2016 (Mw: 6.5) Norcia earthquake recorded at the AVE station; (iii) 19 September 1979 (Mw: 5.9) Valnerina earthquake recorded at ARQ station. The selected time histories were scaled with respect to two PGA values at the MEF site provided by the NTC, 2008: ultimate limit state (SLV) with an occurrence probability of 10% in 200 years. For the MEF site, the code STRATA was used to perform the analyses of local seismic response given the above-mentioned three seismic input motions and seven accelerograms obtained from the Rexel catalogue (Iervolino et al. , 2010) and the subsoil model of Tab. 1. As preliminary results of the site response analysis, the output spectra are compared with the NTC (2008) spectra specific of the MEF site (Fig. 3). We present several output spectra and NTC (2008) spectra considering different configurations as reported in Tabs. 2 and 3. At last, as a first observation, in Fig. 3 we can note that the output spectra are quite similar in shape to, but weakly lower than those of NTC (2008). The results are promising and so, in the next, our effort will be devoted to perform the 2D modelling considering that the subsoil model of the MEF site is very complex because is characterized by vertical and horizontal changing of lithologies and by the presence of cave in the pyroclastic strata, anthropic deposit and rooms in the MEF building basement. Fig. 2 - The G/G 0 vs γ and D vs γ curves adopted for the modelling (see Tab. 1), which were obtained from the borehole S1 soil samples.