GNGTS 2019 - Atti del 38° Convegno Nazionale

380 GNGTS 2019 S essione 2.2 where a g is the peak ground acceleration from PSHA (Probabilistic Seismic Hazard Analysis), F 0 is the amplification maximum value of horizontal spectral acceleration and T C * is the reference value of period of the upper corner period of the constant spectral acceleration range. The aim of this work is to verify the NTC18 amplification factors with an experimental approach, by performing a residual analysis based on the experimental data contained in ESM flatfile (Engineering Strong-Motion; Lanzano et al. , 2019). This flatfile is a parametric table, which contains verified and reliable metadata and ground motion parameters of manually processed waveforms of magnitude M > 4 mainly recorded in Europe and included in the ESM database (http://esm.mi.ingv.it; Luzi et al. , 2016). Dataset of Italian accelerometric stations. We selected 370 Italian accelerometric stations contained in ESM flatfile, having the shear wave velocity profile down to 30 m. Fig. 1 shows the NTC18 classification distribution and we can observe that most of the stations belong to the site classes B and C (51% and 33%), while the soil categories D and E together do not reach 10%. Table 2 - Expression of S S and C C (NTC18). Fig. 1 - Classification distribution of 370 Italian accelerometric stations in ESM flatfile according to NTC18.