PSI - Issue 84

I. Vangelisti et al. / Procedia Structural Integrity 84 (2026) 1239–1246

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and global structural or local structural attention classes. Finally, it identifies general criteria for prioritizing the VAL4 execution on those inspection sections that require it. © 2026 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Conference

Keywords: tunnels; inspections; preliminary safety evaluation; attention class.

1. Introduction The Italian Guidelines for the risk classification, safety assessment, and monitoring of existing tunnels , (D.M. 247/2022), introduce a novel framework for the management of existing road tunnels, based on the so-called “Multi level approach”. This framework defines five levels of activity, ranging from inventory (Level 0) to the assessment of the network resilience (Level 5). The structure of the multi-level approach and the relationships among the different levels, as established by the Tunnels Guidelines, are illustrated in Figure 1.

Fig. 1.

Multi-level according Guidelines.

approach to Tunnels

Within the operational workflow, particular emphasis is placed on the Preliminary Assessment , corresponding to Level 3 (hereinafter referred to as “VAL3”). This assessment aims to collect and critically analyse the information obtained from levels 0 to 2, at least for the High and Medium-High attention classes, and to evaluate the actual need to proceed with further investigations on the tunnel under consideration. The execution of the VAL3 enables the identification of tunnels for which the subsequent assessment levels prescribed by the Tunnels Guidelines are required. However, the Tunnels Guidelines only provide very general criteria for carrying out the VAL3 assessment, granting designers considerable flexibility in the selection of evaluation criteria and structural verification method, although the general principles established by the current regulatory framework (e.g. NTC2018 and its related Circular) remain applicable. The aim of this paper is to propose, in compliance with the principles set in the current regulations, a detailed technical procedure for the execution of the VAL3. The first part of the paper outlines the definition, the scope of application and the objectives of VAL3. This is followed by a discussion of the proposed methodological approach,