Infrastructure Milestone: BESIX and Donati Complete Excavation of the Casacastalda Tunnel in Italy
Casacastalda, Umbria — The joint venture between BESIX (Belgium) and Donati (Italy) has successfully completed the excavation of the Casacastalda Tunnel. Spanning 1,545 meters, this engineering feat represents a major milestone in the modernization of State Road 318 (SS 318). The tunnel is a core component of the 3.13-kilometer Valfabbrica section, a strategic infrastructure upgrade commissioned by ANAS, Italy’s national road authority.
The breakthrough was celebrated during an official on-site event attended by prominent 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 executive leadership of both firms, including Nic De Roeck (General Manager, BESIX Europe) and Angelo Donati (CEO, Donati), joined the technical and engineering teams to mark the occasion.
Technical Precision: Inside the NATM Excavation Process
Underground excavation for the Casacastalda Tunnel commenced in February 2022 utilizing the New Austrian Tunneling Method (NATM). This specialized engineering approach utilizes a sequential excavation design, combining heavy steel arch supports with advanced sprayed concrete (shotcrete) to ensure immediate structural safety and geological stability.
To complete the permanent structure, the tunnel will be reinforced with a robust, cast-in-place concrete lining installed over an advanced waterproof membrane, laying the groundwork for upcoming mechanical, electrical, and roadwork installations.
Navigating the engineering constraints required meticulous precision, as Hervé Jourquin, Deputy Project Manager at BESIX, highlighted:
“Excavating a new tunnel directly adjacent to an active, high-traffic tunnel is an extremely delicate operation. We had to continuously monitor the adjacent active tunnel to prevent any structural impact or traffic disruption, all while navigating highly complex geological strata, including multicolored clays and the challenging Marnoso-Arenacea formation.”
For a deeper look into underground structural standards and the physics behind modern sequential drilling, explore the technical guidelines provided by the International Tunnelling and Underground Space Association (ITA-AITES).
Expanding the Core Trans-European Transport Network (TEN-T)
The Casacastalda Tunnel is a cornerstone of a broader €132 million infrastructure investment designed to optimize traffic flow, reduce transit times, and elevate road safety standards between Perugia and Ancona.
The complete Valfabbrica infrastructure corridor encompasses several major structural builds:
- The Picchiarella Tunnel: An 874-meter underground passage.
- The Tre Vescovi Viaduct: A 130-meter elevated roadway.
- The Calvario Bridge: A 60-meter structural crossing.
Once fully operational, this updated network will drastically improve critical east-west connectivity across Umbria and the Marche region, bridging essential commercial routes. To view broader traffic impact assessments and European corridor developments, track regional data updates via the European Commission’s Mobility and Transport portal.
Project Timeline: The Next Phases of Development
With the primary excavation phase successfully completed, the joint venture is shifting its operational focus to the final stages of the project lifecycle. Upcoming milestones include:
- Structural Lining & Waterproofing: Finalizing internal structural shells to mitigate water ingress.
- Systems Integration: Installing state-of-the-art hydraulic, mechanical, ventilation, and electrical systems.
- Surface Work: Final asphalt paving, safety barrier installations, and seamless integration into the active SS 318 road network.
Originally awarded in 2020, the infrastructure project remains strictly on schedule for its final handover in 2026.
Looking Ahead: Expanding Infrastructure in Ancona
Building on the momentum of the Umbria breakthrough, BESIX and Donati are set to collaborate with ANAS on a subsequent major infrastructure initiative in Ancona. This upcoming project features a 1.8-kilometer road section containing two new tunnels and a modern viaduct, further upgrading the vital SS 76 corridor—a critical logistical vein in Italy’s national road network.
Jan Van Steirteghem, COO Construction at BESIX Group, reflected on the joint venture’s trajectory:
“This is a proud moment for our teams. It confirms our deep engineering expertise in delivering technically complex, high-risk infrastructure projects safely and efficiently. Furthermore, it strengthens our long-standing corporate partnership with Donati and ANAS.”
To learn more about the civil engineering portfolio and international project updates of the primary contractor, visit the official BESIX Group website.
