PSI - Issue 78

Gabriele Fiorentino et al. / Procedia Structural Integrity 78 (2026) 245–252

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(synthetic) ground motions is justified by the fact that for Magnitude-Distance combinations consistent with the scenario earthquake (M 6.8-7.1, R epi 5-15, Soil B class), the number of available records in the ESM database was insufficient. For the sake of comparison, the search parameters were modified to M 6.6-7.7, R = 0-20 km, and any site condition, allowing for the identification of 10 possible records (each with two horizontal components). The natural records were then scaled with a Genetic Algorithm to find the most suitable combinations of records (See Figure 4 and Table 2). Scale factors were kept in the range 0.5-2.

Fig. 4. ( a) Spectrum-compatible response spectra of s imulated ground motions defined with SIGMA (Fiorentino et al., 2025); (b) Spectrum compatible response spectra of natural ground motions obtained using a Genetic Algorithm for the selection.

Table 2. Parameters of the natural records extracted from the European strong motion database and scaled with a genetic algorithm procedure Earthquake Date Comp Station Mw R epi (km) V S30 (m/s) SF PGA (g) TK-1999-0415 1999-11-12T16:57:22 U C1058 7.2 18.0 893 0.96 0.108 TK-1992-0002 1992-03-13T17:18:39 U 2402 6.6 12.8 337 1.44 0.487 IT-1980-0012 1980-11-23T18:34:53 U CLT 6.9 18.9 557 0.71 0.175 ME-1979-0003 1979-04-15T06:19:44 U ULO 6.9 14.1 397 0.80 0.237 UZ-1976-0001 1976-05-17T02:58:40 U GZL 6.7 3.4 - 1.52 0.722 TK-1999-0415 1999-11-12T16:57:22 V 8101 7.2 5.4 278 1.83 0.414 INT-UT19990920_174715 1999-09-20T17:47:18 V B078 7.7 14.6 396 1.95 0.305 INT-UT19990920_174715 1999-09-20T17:47:18 V B079 7.7 11.7 970 0.91 0.420 INT-UT19990920_174715 1999-09-20T17:47:18 V B089 7.7 19.5 1012 0.96 0.229 ME-1979-0003 1979-04-15T06:19:44 V ULA 6.9 13.1 870 1.67 0.176 Figure 5 shows the displacement response spectra of the natural ground motions. It is possible to notice that, for vibration periods around 1.09 and 2.12 s, maximum displacements of 30 to 60 cm can be obtained, depending on the case considered.