PSI - Issue 84

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ScienceDirect

Procedia Structural Integrity 84 (2026) 867–873

© 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 The new precast is also connected to the remaining part of old lining in order to ensure structural safety to the tunnel; furthermore, during each night closure, the removal of old lining is limited to the extent that corresponds to precast elements that can be permanently connected to each other: in the remaining part of the tunnel the old lining is left in place until the next phase. After an application of this technique for a tunnel on a low traffic road in Marche Region, renovation works are about to start for a twin-bore tunnel on a busy motorway around the city of Perugia (Umbria Region), where road closures have a strong impact over traffic congestion in city centre itself. III Fabre Conference: Existing Bridges, Viaducts, and Tunnels: Research, Innovation, and Applications Innovation in Tunnel Renovation Works to Reduce Impact of Road Closures: The Use of Precast Elements for New Linings Enrico Mittiga a, *, Domenico Renda a , Michele Consumini a , Nicola Mangialardi a a Anas SpA – Gruppo Ferrovie dello Stato Italiane, Via Monzambano 10, Roma 00185, Italy Abstract Anas SpA – Gruppo Ferrovie dello Stato Italiane, the Italian national road company, is owner of a network of over 32,000 km of roads, with more than 19,000 bridges and 2,100 tunnels. Specific inspection and maintenance strategies, following new technical guidelines from the Ministry of Infrastructures, are implemented to assess the structural health and safety of each structure: therefore, necessary renovation works can be properly planned. However, any renovation work means disruption and discomforts for traffic. When it comes to tunnel renovation works, the choice of techniques to reduce as much as practicable the duration of road closure is crucial to minimize the impact on high traffic level roads. In this sense, Anas is implementing the use of precast lining for road tunnels renovation; precast elements are put in place after the mechanical removal of the old concrete lining (completely or in part only), requiring very limited quantity of concrete placements. This technique allows tunnel closures to be limited to nighttime hours only, and traffic to be restored the following day, immediately after the working equipment has been removed. When joined together the precast elements are self-supporting and they do not need any props, leaving the platform free from obstructions.

* Corresponding author. Tel.: +39 331 7532 512. E-mail address: e.mittiga@stradeanas.it

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.2026.06.111