PSI - Issue 84

Available online at www.sciencedirect.com

ScienceDirect

Procedia Structural Integrity 84 (2026) 1239–1246

III Fabre Conference: Existing Bridges, Viaducts, and Tunnels: Research, Innovation, and Applications A comprehensive methodology for the execution of the preliminary safety evaluation VAL3 for existing tunnels in compliance with the Italian Guidelines for risk classification, safety assessment, and monitoring of existing tunnels I. Vangelisti a, *, W. Salvatore b , F. Morelli b , D. Peila c , A. Carigi c , G. Bordi d , V. Farmeschi d , V. Prisco d , C. Bonaldi e a Consorzio FABRE, Consorzio di ricerca per la valutazione e il monitoraggio di ponti viadotti e altre strutture, Largo Lucio Lazzarino 1 – Pisa, 56122, Italy b Università di Pisa, Lungarno Pacinotti 43 – Pisa, 56126, Italy c Politecnico di Torino, Corso Duca degli Abruzzi 24 – Torino, 10129, Italy d SINA S.p.A, Viale Isonzo 14/1 – Milano, 20135, Italy e Autostrada dei Fiori S.p.A. - Via della Repubblica, 46 - 18100 Imperia Abstract The Italian Ministerial Decree 247/2022, "Guidelines for risk classification, safety assessment, and monitoring of existing tunnels", introduced a new framework for the management of existing tunnels, defined as multi-level approach and based on five levels of activity: inventory (level 0), inspection (level 1), attention class (level 2), preliminary safety evaluation (level 3), detailed safety evaluation (level 4), and network resilience assessment (level 5). While the Guidelines supply detailed practical information and procedures for the execution of level 0 to level 2 activities, for level 3 and level 4 they provide only general criteria for performing these evaluations, thereby granting designers substantial latitude in specifying procedural details. In this paper, a comprehensive methodology for the execution of level 3 (VAL3) – developed in compliance with the general principles set out in the Guidelines - is proposed. It highlights when VAL3 is required, outlines the workflow for its development, and focuses on inspection segments for which a reduction of the originally assigned attention class is deemed appropriate. To assess the effectiveness of the proposed procedure and highlight eventual practical implications, it is then applied to real existing tunnels classified with high geotechnical

* Corresponding author. E-mail address: iacopo.vangelisti@gmail.com

2452-3216 © 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 10.1016/j.prostr.2026.06.159