Road rehabilitation works between Etroubles and the highway junction for the San Bernardo Tunnel (Italy)

The project aims to bypass the area of St. Oyen located a few kilometers from the Gran S. Bernardo tunnel. The new alignment follows a completely different route from the existing one. The present road, which runs from the tunnel junction to Aosta, is a single carriageway with two traffic lanes, one in each direction. It is the only communication route and has a fairly fluid course which undergone considerable improvements and widening over the years. However, in one section of approx. 3.5 km (between Etroubles and St. Oyen, from km 15+180 to km 18+700), the road alignment is quite winding with considerable slope and needs some improvements. The project will create a variant to the present road passing through St. Oyen by building a paved road tunnel, inside St. Oyen municipality (from Km 16+800 to Km 18+700). The project foresees a C2-type road platform (according to the Ministerial Decree 5/11/2001) for a total width of 9.50 m; it’s formed by two lines (one for each way) with a width of 3,50 m each and a shoulder road of 1,25 on both sides. The new road is characterized by a natural tunnel measuring more than 3,500 m and by two viaducts with a mixed structure in steel and concrete and a 90 m central span, so that the total length of the new roads is over 4,000 m. The project connects the new alignment to the old road with two wide roundabouts on both sides. The tunnel follows a significantly curved alignment because of the need not only to connect to the junctions at both ends, but also to find the maximum cover at the junctions with a layout that must be as orthogonal as possible to the contour lines. This design complies with existing EU standards.