Statistical analysis of risk assessment of bridges and viaducts according to recent Italian guidelines

The safety assessment of existing bridges and viaducts is nowadays a critical task. Several works have been published in recent years relying on multi-risk based approaches, then aiming to properly evaluate the various risk sources involved in the identification and evaluation processes of existing infrastructures. In Italy, after some significant collapses (the most famous case is certainly the Polcevera viaduct, also known as the Morandi’s bridge, collapsed in 2018), the Italian Higher Council of Public Works provides specific regulations, the 2020 Guidelines (updated in 2022), intended to standardize the entire risk classification procedures and monitoring activities of existing bridges and viaducts for the whole Italian road network. This work proposes two main contributions. The first concerns a conceptual analysis of the logical path that leads from the considered parameters to the risk classification (class of attention, according to the cited Guidelines). The aim is to enucleate the total amount of parameters, their role and the possible combinations. The second contribution concerns an extensive investigation on the statistics of the class of attention. Such statistics represent the “a priori” distributions of the multi-risk procedure indicated by the regulation.