Road Axis between Marches and Umbria Regions and Quadrilateral of Internal roads: Completion of state highway SS 77 “Val di Chienti”

The project concerns the completion of a road network across Umbria and Marches Regions, in the Provinces of Perugia and Macerata, for a total of 93 km, including a 38.7 km-long dual-carriageway fast highway and 54.3 km of extra-urban roads. 

The B category roads have a design speed 120 km/h, 2 carriageways each with 2 lanes 3.75 m width + shoulders 1.75 m right / 0.50 m left, and (minimum) 2.5 m wide traffic island. The C category roads have a design speed 100 km/h, with a single carriageway with variable width.

The main axis is the State Road SS 77 between Foligno and Pontelatrave (34.7 km long), consisting of 23 km in twin tunnels (2 separate tubes for the carriageways, 35 m inter-axis), 9.4 km on embankment (maximum height around 10m), 2.4 km on viaducts. The road includes four (2-level) interchanges.

Long tunnels, up to 4 km long, are required, having a cross-sectional area of 120 m² and an internal width around 12 m. The tunnel design includes mechanical and electrical installations (lighting, fire-fighting, forced ventilation, safety equipments signs, monitoring, communication system, etc.).

Viaducts are composed of precast concrete girders (shorter spans, up to 36 m) or composite steel-concrete decks (longer spans, variable up to 80 m). The maximum pier height is around 30 m, with foundations generally on piles or shafts, due to the unfavourable soil conditions and the high seimicity of the site.

The contract includes the following activities:

• Design of major and minor structures (viaducts, tunnels, retaining structures etc.) in seismic area
• Design of mechanical and electrical installations 
• Environmental impact monitoring
• Design of geological/geotechnical survey