PSI - Issue 44

Brunella Cutrone et al. / Procedia Structural Integrity 44 (2023) 713–720 Brunella Cutrone et al. / Structural Integrity Procedia 00 (2022) 000–000

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1. Introduction Italy has a geographic and orographic conformation unique in the world: the mountain ranges of the Alps and the Apennines, which cross our territory transversely and longitudinally, and the network of waterways distributed in a capillary manner, make viaducts, bridges and tunnels essential elements for traffic. This work is part of the identification and subsequent classification of landslide risk for existing bridges. Nomenclature ANSFISA Italian National Agency for Safety of Railways and Roads MIMS Italian Ministry for Sustainable Infrastructure and Mobility Bridge Guidelines Italian guidelines for classification, safety assessment and monitoring of existing bridges IFFI Project Italian Landslide Inventory Project ISPRA Higher Institute for Environmental Protection and Research PAI Hydrogeological Arrangement Plans CNR-GNDCI National group for the defense of hydrogeological disasters - National Research Council AVI Areas historically vulnerable to geological disasters GSI Geological Service for Italy - Cartographic organ of the state CARG Project GSI Project on Geological and geothematic cartography SNPA National System for Environmental Protection - ISPRA IdroGEO Platform Italian platform on hydrogeological instability – ISPRA SMS Safety Management System - Ansfisa RISM Road Infrastructure Safety Management – ITF The hydrogeological instability is a topic of particular importance for Italy due to the impacts on population, environment, cultural heritage, infrastructures and on the economic and productive fabric. The natural propensity of the territory to instability, in fact, linked to its weather-climatic, topographic, morphological and geological characteristics, is added the fact that Italy is a heavily man-made country. The increase in urbanized areas, which took place after II World War, often in the absence of correct territorial planning, led to a considerable increase in the elements exposed to risk, in other words, of goods and people present in areas subject to danger due to landslides and floods. The predisposition of the Italian territory to landslides therefore translates into a significant possibility of interactions with the roadworks of the national network. In this context, it is therefore essential to develop effective techniques for the characterization of unstable areas in the territory. However, the absence of monitoring and the inability to apply them to the entire territory, for reasons of affordability and practicality, in light of the extent of the problem, make this characterization often difficult. The paper proposes an analysis of the assessment parameters of the attention class relating to hydrogeological risk, in order to optimize the application of the Bridge Guidelines (MIMS, 2020) by limiting the subjectivity in the assessment, aspects also discussed by other authors (Bazzucchi,2018, Buratti,2022, Santarsiero,2021, De Matteis, 2022).In particular, some methods are presented to determine the propensity for failure of the investigated area, in order to avoid that lack of initial information (or their reliability) leads to the failure of the risk analysis. At the same time, methods were proposed to estimate the parameters necessary for determining the hazard level associated with the bridge landslide attention class, with the aim of limiting the uncertainty of the assessment. 2. Hydrogeological instability in Italy: susceptibility and risk indicators Landslides in Italy are extremely widespread on the national territory and are natural disasters that are repeated more frequently and, after earthquakes, cause the greatest number of victims and damage to inhabited centers, infrastructures, environmental, historical and cultural assets. From the end of the II World War to date there has been an increase in the risk of landslides due to the growing anthropization of the territory, with an expansion of the urban fabric often in unstable areas. The increase in urbanized areas, often occurring in the absence of proper territorial planning, has led to a considerable increase in the elements exposed to risk. Artificial surfaces in fact went from 2.7% in the 1950s to 7.11% in 2020 and at the same time the abandonment of mountain and hilly rural areas resulted in a