Casacastalda, Umbria – June 2025 — The joint venture between BESIX (Belgium) and Donati (Italy) has successfully completed the excavation of the Casacastalda Tunnel, a 1,545-meter structure that represents a major advancement in the enhancement of State Road 318 (SS 318). The tunnel is part of the 3.13-kilometre Valfabbrica section, a strategic infrastructure upgrade commissioned by ANAS, Italy’s national road authority.
The achievement was marked by an official on-site event attended by regional and national dignitaries, including Francesco De Rebotti, Councillor for Economic Development, Labour Policies, Mobility and Infrastructure of the Umbria Region, and Lamberto Nicola Nibbi, Head of ANAS Umbria. The leadership of both BESIX and Donati, including Nic De Roeck (General Manager, BESIX Europe) and Angelo Donati (CEO, Donati), joined the celebration alongside technical teams and partners.
🔹 A Technically Demanding Milestone
The tunnel excavation began in February 2022, employing the New Austrian Tunneling Method (NATM) — a specialized technique that combines steel arch supports with sprayed concrete to ensure underground safety and stability. The structure will be reinforced with a cast-in-place concrete lining over a waterproof membrane, forming the base for mechanical and roadwork systems.
“Excavating a new tunnel adjacent to a traffic-active tunnel is an extremely delicate operation,” said Hervé Jourquin, Deputy Project Manager, BESIX.
“We had to continuously monitor the adjacent active tunnel to prevent any disruption or structural impact, all while navigating complex geological strata, including the multicolored clays and Marnoso-Arenacea formation.”
🛣️ Broader Infrastructure Scope
The Casacastalda Tunnel is just one part of a larger €132 million project aimed at improving traffic flow and road safety between Perugia and Ancona. The complete Valfabbrica section also includes:
- The 874-meter Picchiarella Tunnel
- The 130-meter Tre Vescovi Viaduct
- The 60-meter Calvario Bridge
Once complete, the new infrastructure will greatly enhance east-west connectivity across Umbria and the Marche region.
🔄 What’s Next
With excavation now finalized, the next phases include:
- Tunnel lining and waterproofing
- Installation of hydraulic, mechanical and electrical systems
- Final surfacing and integration with existing road networks
The project, awarded in 2020, remains on track for completion in 2026.
🏗️ Looking Ahead: Next Joint Project in Ancona
Following this success, BESIX and Donati will collaborate with ANAS once again on a new infrastructure initiative in Ancona. This upcoming project includes a 1.8-kilometre road section featuring two additional tunnels and a viaduct, further enhancing the SS 76 corridor, a vital link in Italy’s national road system.
“This is a proud moment for our teams,” said Jan Van Steirteghem, COO Construction, BESIX Group.
“It confirms our expertise in delivering technically complex infrastructure projects safely and efficiently — and strengthens our long-standing partnership with Donati and ANAS.”
