PSI - Issue 78

Carpanese Pietro et al. / Procedia Structural Integrity 78 (2026) 536–543

539

is 850 €/m 2 . The content value is closely linked to the type of activity and should be assessed on a case-by-case basis: in the absence of more detailed information, Hazus (FEMA 2022a) technical manual was used, which expresses the content value as a percentage of the building value (150%). 3. Hazard The PERIL platform indicates for each input building an hazard class from P1 (minimum hazard) to P4 (maximum hazard), with in some cases the possibility of P0 (no hazard), for the following events: earthquake, flood, landslide, hail, wind, and lightning. Further detail is presented for earthquakes and floods, reporting quantitative values for different scenarios or return periods, which are later used by the platform to perform risk analyses. 3.1. Seismic hazard Regarding seismic hazard, PERIL returns the value of the maximum horizontal ground acceleration a g [g], the maximum value of the amplification factor of the horizontal acceleration spectrum F O , and the period of start of the constant-velocity section of the horizontal acceleration spectrum T C * [s] for 9 return periods TR (30 years, 50 years, 72 years, 101 years, 140 years, 201 years, 475 years, 975 years, 2475 years). These values are provided by the current standard NTC2018 (Italian Ministry of Infrastructures and Transports 2018, Annex B of Italian Ministry of Infrastructures and Transports 2008) for 10,751 points of a grid defined with 0.05 degree step. The values of the three parameters can also be derived for points in Italy not corresponding to the ones on the grid, by interpolation of the values assumed by these parameters at the four nearest vertices, following the procedure given in Annex A of NTC2008 (Italian Ministry of Infrastructures and Transports 2008). The classification (P1-P4) is produced from the a g values defined for a return period of 475 years as follows: P1 for a g ≤ 0.05g, P2 for 0.05g < a g ≤ 0.15g, P3 for 0.15g < a g ≤ 0.25g, and P4 for a g > 0.25g. The aforementioned seismic action values refer to a standard condition of rigid soil and horizontal topography. Differences in soil type and more articulated topographic configurations can also significantly influence the propagation of seismic action from the epicenter, which can result in a significant increase in the local detected acceleration. Therefore, PERIL also returns the soil class A-D and topographic class T1-T4, according to NTC2018 classification (Italian Ministry of Infrastructures and Transports 2018), as well as the amplified a g value obtained by considering soil specifications. The soil class was derived using the map of average shear wave propagation velocity values for the first 30 meters V S30 by Mori et al. (2020), while the topographic class was calculated based on the procedure proposed by Pessina and Fiorini (2014). Th flood hazard of the PERIL platform refers to food hazard maps provided by ISPRA (Institute for Environmental Protection and Research) (https://www.isprambiente.gov.it/pre_meteo/idro/Mappe_peric.html). In particular, three types of maps were used. The first map is related to the extent of the floodable area that identifies areas prone to flooding for three different probability scenarios: high probability hazard (HPH), medium probability hazard (MPH), and low probability hazard (LPH). The return periods related to each scenario are locally defined, but can approximated to an average of 30 years for HPH, 150 for MPH and 400 for LPH. This map is used in PERIL to define whether or not a building is subject to the flood event for the analyzed scenario. The second type of map relates to the hydraulic characteristics of the flood event, which is essential for making risk calculations. In particular, ISPRA maps provide the height of the water (h) and the flow velocity (v) in the floodable areas for the three previously defined probability scenarios (HPH, MPH, LPH). These maps are not available for the entire Italian territory, so in case of missing data PERIL returns a statistically defined default value. The last map define four risk classes (R1 moderate, R2 medium, R3 high, and R4 very high) based on social, economic, and environmental heritage damage. The risk classes P1-P4 proposed by PERIL thus correspond to the hazard classes provided by ISPRA (R1-R4), with the addition of a P0 class assigned in case the building is located in non-floodable areas. 3.2. Flood hazard