PSI - Issue 44

Mariano Angelo Zanini et al. / Procedia Structural Integrity 44 (2023) 665–672 Mariano Angelo Zanini et al. / Structural Integrity Procedia 00 (2022) 000–000

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3

a)

b)

c)

d)

Fig. 1. Two-span RC arch bridge case study (a) and original drawings with reinforcement detailing of the deck (b), pier (c) and arches (d) (from Ufficio del Genio Civile di Vicenza 1948). To compute "# , the seismic hazard map for Italy, provided by the National Institute of Geology and Volcanology (INGV), was used. The map is based on a 5-km span grid and, for each node, seismic hazard data are provided, with reference to nine return times, that correspond to exceedance probabilities of 2, 5, 10, 22, 30, 39, 50, 63 and 81% in 50 years, respectively. To compute the failure rate a continuous hazard function is needed. Since INGV provides hazard data (values of the 16 th , 50 th and 84 th percentile) only for nine return times, median values were fitted with a quadratic function in the logarithmic space as: ( ) = / ('1 " 23(4)'1 # 67 # (4)) (6) In assessing seismic reliability, instead of the median hazard curve, it is more suitable to refer to the mean one which is possible to derive with the following equation: