A new methodology for the multi-risk assessment of existing road tunnels

The optimal management of infrastructural assets is a key aspect to guarantee the adequate competitiveness of a country from the economic point of view and a good level of quality from the social one. In this framework, particular attention shall be paid to the critical elements of the infrastructure network, such as bridges and tunnels, which often strongly influence the resilience of the network itself, as highlighted both by what happened immediately after the collapse of the Morandi bridge in Genoa and by the situation that was created following the several construction sites implemented to reduce the structural risk in the tunnels of Ligurian territory. Indeed, on one hand these critical elements are often characterized by lower structural safety levels than those required by the regulations for similar newly built structures but, on the other hand, the presence of construction sites determines a reduction in the performance of the infrastructure with a significant increase of the road accident and traffic risk. This paper proposes an operational methodology for assessing the risk associated to existing road tunnels. The research is carried out in collaboration with SINA SpA and ASPI, Autostrade per l'Italia, and has the main objective of providing practical tools that can help the road managers to evaluate the global risk variation when temporary interventions are carried out in tunnels and to give indications regarding the optimal construction site organization.