PSI - Issue 62

Giada Limongi et al. / Procedia Structural Integrity 62 (2024) 97–104 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

99 3

Municipalities classified as intermediate (D), peripheral (E), and ultra-peripheral (F) are defined as inner areas. Following the SNAI classification, it is possible to define the presence of an adequate road alternative if there is an alternative of equal or higher road level that allows to reach the nearest municipal (A) or intermunicipal (B) center in a travel time that does not exceed the threshold value of the assigned SNAI class. If, instead, the identified alternative allows to reach the municipal (A) or intermunicipal (B) center in a time exceeding the threshold value of the SNAI class, by worsening the peripherality of the municipality, the condition of "absence of alternatives" can be assumed and, therefore, the exposure class of the bridge must be increased. 3. Test case The proposed method is tested on the network of provincial roads connecting the inner areas of the Province of Caserta with the respective center (A or B) identified by the SNAI. Of the 104 municipalities in the Province of Caserta, 2 are classified as municipal centers (A), 45 as belts (C), 34 as intermediates (D), and 22 as peripherals (E). According to the 2020 update, none of the 104 municipalities is classified as peripheral (F). On the initial set of 640 bridges along the provincial road network (Zizi et al. 2023), those tested are located along the roads connecting each municipality classified as an inner area (D-intermediate or E-peripheral) with the respective center (A or B) identified by the SNAI. The route identified is the shortest one. Then, the first equal or higher-level alternative is considered, and the travel time is recorded. If the alternative travel time does not exceed the threshold value of the SNAI class to which the municipality belongs, the road alternative can be considered adequate and the assigned exposure class for the bridges along the main municipal inner area-center route does not change. If the travel time of the road alternative exceeds the threshold value of the class to which the municipality belongs, the road alternative cannot be considered adequate and the assigned exposure class for the bridges along the main municipal inner area-center route must be increased for lack of road alternatives (Fig. 1).

Fig. 1. The methodological steps.

The municipalities involved in the test case are those classified as intermediates (D), and 22 as peripherals (E). The bridges located along the main inner area-center routes are 150 (Fig. 2) along the provincial roads listed in table 1. Considering their potential interruption, in 18 of the 56 considered municipalities, the travel times of the alternative route exceed the threshold value of the respective classes. In 14 municipalities the increase in travel time determines the transition from intermediate (D) to peripheral (F), for the other 4 it moves from peripheral (E) to ultra-peripheral (F). As a result, the lack of adequate road alternatives leads to an increase in the assigned exposure class for 68 bridges (Fig. 3). See Annex A for data.