A1 Highway, Valico Bypass, Italy

Italy, the land of good, healthy food with the Made in Italy label, of imposing architecture that exudes history and knowledge, of historic cities, of varied landscapes that alternate harmoniously between sea, hills and mountains. These are the aspects that have always made trade and tourism flourish.

One of the direct consequences of these many riches is the volume of road traffic that travels daily between the different parts of Italy, especially from north to south, causing frequent traffic jams, especially in some areas of the Belpaese. For this reason, the widening of the A1 motorway, which includes the construction of the Valico bypass in the 62.5 km Apennine section between Sasso Marconi and Barberino del Mugello, is a key project in terms of connections and traffic flows. It involves the symbolic work of the Variante di Valico, that is Galleria di Base, which was constructed by means of a tunnel with separate lanes, approximately 8.6 km long, with a minimum cross-section of 180 square metres.

The total length of the structure was 11.2 km and, in addition to the iconic base tunnel, three viaducts were built using a modern steel and concrete structure. In addition, the Badia junction had to be built, with four additional entry and exit ramps; the Poggiolino junction and snow storage facility; and a junction between the Poggiolino junction and the town of Montecarelli, which required the construction of three viaducts.

In addition, along the tunnels, which were built using traditional excavation methods, some sections were reinforced with special types of crown and pre-coating materials, several bypasses for vehicles and pedestrians were built, a ventilation system with jet and axial fans was installed, and a Remote Control System for all the systems present was installed in order to guarantee maximum safety in the tunnel.

A project of enormous importance, in which technological innovation played a key role in overcoming the main challenge of the work: ensuring safety in a difficult environment such as this, where the tunnels have high concentrations of methane. For this reason, various measures were taken to protect the many people working on the project, such as the conversion of vehicles, plant and equipment to AD equipment, the continuous measurement of methane levels and the use of non-electric explosives.

The Variante del Valico, together with its ventilation management method, is now a benchmark of excellence in road construction, as evidenced by the awards it has received: many international visits, organised by the University of Florence and the Alma Mater Studiorum of Bologna, and awards received by the yard's employees for their commitment to improving safety on the site, as part of the "VAV Incentives for Safety" awareness-raising project.