The Loures Valley viaduct has a length of 1614m. The valley topography, the height of the alignement and the high local seismicity advised to divide the viaduct in two independent sections each one being constituted by two parallel decks with a total width of 34.7m. Both viaducts were totally cast “in situ”.
Both decks of the south viaduct are fully continuous longitudinally prestressed box girders with spans of 62.0 + 9 x 80.0 + 44.0m, crossing the valley at height of almost 70m. This 826m viaduct was built by the balanced cantilever method in 5.0m segments.
The piers, in reinforced concrete, have a box shape with variable cross-section. The pile foundations have diameters of 2.0m with an average depth of 18m.
The north viaduct has a total length of 784m distributed over 20 spans of 32.0 + 18 x 40.0 + 32.0m. Each deck has two continuous longitudinal beams 3.0m high connected together by a reinforced concrete deck slab and prestressed cross-beams. The decks were cast span-by-span with under-slung self-launching form-carriers.
The piers are in reinforced concrete, with a tubular cross-section. The heads were specifically designed to allow the launching of the form-carriers through them. The foundation piles have 1.5m diameter and have an average depth of 16m.
The viaduct was completed in 1995.