GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 2.2 GNGTS 2023 Figure 2. The Italian national gas pipeline network and the analysed Malborghetto-Flaibano pipe #048. A set of 100 spatially correlated ground motion fields were generated as described above for the stochastic simulation of peak ground velocity (PGV) spatial distribution generated by the Mw 6.4 1976 Friuli earthquake. The GMPE of Bindi et al. (2011) was adopted for the characterization of the fields: Figure 3a shows, as example, ground motion field #12. For each PGV field structural damages to the different parts of the pipe #048 have been assessed through fragility curves of Lanzano et al. (2013) in terms of release states and associated probability values. The following consequence radius values were assumed: - RS1: 137 m (Jet fire of 37.5 KW/m2) – 341 m (VCE 0.3 bar) – 1383 m (Flash fire); - RS2: 137 m (Jet fire of 37.5 KW/m2) – 341 m (VCE 0.3 bar) – 1383 m (Flash fire). Each of these consequence radius values were subsequently weighed with probability values derived from fragility curves and the event tree diagram illustrated in Figure 1 leading to define an average consequence radius adopted as indicator criterion for the identification of the pipe segments mostly affected in case of Friuli earthquake scenario recurrence. Figure 3b shows the 95th percentile envelope result, representing in green average consequence radius values lower than 200m, in yellow values in the range 200 – 400 m and in red the ones higher than 400m.