A record-breaking construction site in the heart of Lombardy: a fleet of seven hydro-cutters will lead the underground excavation work for the New Lombardy Pedemontana Motorway, setting a new record in the Italian infrastructure sector.

Work is proceeding according to schedule on Sections B2 and C of the New Pedemontana Lombarda Motorway, confirming its status as one of the most strategically important infrastructure projects in Northern Italy. The motorway is designed to strengthen links between Como, Varese, Milan, Monza and Brianza, and Bergamo, relieving traffic on the existing network and optimising the flow of people and goods by road.

To carry out the project, the consortium partnership between Impresa Pizzarotti and Webuild, on behalf of the client Autostrada Pedemontana Lombarda, will deploy up to seven hydro-cutters simultaneously.

The project stretches for over 26 kilometres between Lentate sul Seveso and the junction with the A51 Milan East Ring Road at Usmate Velate, passing through one of the most urbanised and productive areas in Europe.

The complex engineering solution stems from the fact that around 85 per cent of the route will run through cuttings or tunnels to minimise visual and noise impact, whilst safeguarding road networks and restoring green spaces and public areas at ground level.

The main challenge centres on Section C, which stretches for over 16 kilometres between Cesano Maderno and Usmate Velate. Here, to overcome the hardness of the ‘Ceppo della Brianza’ – a compact conglomerate as hard as lean concrete – the site has introduced hydro-cutters: colossal machines over 24 metres tall and weighing 400 tonnes, which guarantee an extraordinary increase in productivity, achieving 3–4 diaphragm walls per day per machine to a depth of up to 40 metres, for a total potential of around 130 diaphragm walls per week.

The hydro-cutters utilise a continuous bentonite slurry circuit that supports the excavation walls whilst extracting debris to the surface. These machines are the driving force behind the renowned ‘Milan Method’, the construction solution chosen for the Desio and Macherio tunnels, which involves the prior construction of the walls and the underground roof before proceeding with the excavation of the subsoil, thereby minimising noise, dust and disruption to urban traffic.

Taken together, the two sections represent a model of smart and sustainable infrastructure that combines advanced traffic management technologies with the specialist expertise of the Pedemontana Nuova consortium in the field of underground excavation and large-scale complex projects.