Two newly constructed road tunnels on Umbria’s SS318 corridor have opened to traffic.
The Valfabbrica infrastructure project, delivered by a Besix and Donati joint venture, is part of the modernisation of the SS310 corridor – a strategic route connecting central Italian regions and improving connections between Perugia and Ancona.
Commissioned by Italy’s national road authority, Anas, the 3.13km section included the construction of the 1.55km-long Casacastalda Tunnel and the 874m-long Picchiarella tunnel, as well as the Tre Vescovi viaduct and the Calvario bridge, upgrades to existing tunnel infrastructure, and improvements to surrounding road sections.
This week, traffic was diverted through the newly built tunnels to allow the project team to focus on rehabilitating the existing tunnels, including safety system upgrades, new lighting system, compliance works, cleaning and repainting.
The traffic diversion marks the start of the project’s final phase. Over the coming eight weeks, Besix and Donati will complete the remaining refurbishment works before handing over the infrastructure to ANAS shortly before mid-November.
Excavation of the Casacastalda Tunnel, using the NATM, began in February 2022 and was completed in June last year. The teams used steel arch supports and sprayed concrete to stabilise the tunnel. It was completed using cast-in-place concrete lining, placed over a waterproofing membrane.
At the time, Besix deputy project manager Hervé Jourquin said excavating a tunnel adjacent to an operational tunnel was a delicate task.
“Any error could have dramatic consequences,” he said.
The tunnelling crews also had to negotiate complex geology of multi-coloured clays and the Marnoso-Arenacea formation.
