PSI - Issue 44

Brunella Cutrone et al. / Procedia Structural Integrity 44 (2023) 713–720 Cutrone,Salvatore,Renzi and Tamasi / Structural Integrity Procedia 00 (2022) 000–000

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(modified Stevenson method) (Pellicani et al., 2017, Pellicani, 2013, Pellicani et al., 2013); it allows to calculate a susceptibility index according to an algorithm that combines five predisposing factors, weighted according to the influence they exert on the entire instability process.

Fig. 2. Landslide Susceptibility Index Calculation. (Pellicani,2013).

In order to analyze the survey site of a bridge, it is necessary in a first phase to create thematic maps relating to the predisposing factors, i.e. plasticity index, water factor, slope, complexity and land use, in a GIS environment. Subsequently, in the calibration phase of the model, the weights to be assigned to each factor must be calculated according to a bivariate statistical procedure, which, through the comparison between the landslide inventory map and each thematic map, provides for the calculation of the landslide density both in the study area is within each of the three classes into which the thematic maps are divided. By implementing the calculation algorithm, a representative map of the spatial distribution of point values of the susceptibility index can be obtained; subsequently the map is then reclassified in order to divide the territory in question into zero, low, medium and high susceptibility areas.

Fig. 3. Susceptibility maps (Pellicani, Argentiero, Spilotro, 2017)

The importance of the proposed method therefore lies in the possibility of using a predictive model of susceptibility more easily manageable than statistical methodologies and easily adaptable to the specific context and the availability of data with the introduction or elimination of predisposing factors.