Северо-восточная автострада А-6 участок «Амбасместас-Кастро/Ламас» (Леон – Ла Корунья»

The recent works to construct 8.5 km. along the Ambasmestas – Castro/Lamas section of the A-6 motorway between Madrid and La Coruña, completed in 2001, have become a reference in Spanish civil engineering for various reasons: their huge economic value, modern design, high technical difficulty, derived from significant geological and hydrological issues that were eventually resolved the application of huge avant-garde technological solutions, and the high quality of the product obtained.

In 2003, the works were awarded the famous "Puente de Alcántara" International Prize. The jury pointed out "the suitable use of imaginative and daring geotechnical solutions in an extremely complex project, from a technical point of view, which has enabled an exemplary interaction between the motorway course and the complex characteristics of the land, and a suitable protection of nature and other areas of cultural interest".

One of the most outstanding access points from Galicia to the plateau has traditionally been the link between the provinces of Leon and Galicia through Puerto de Piedrafita, at a height of 1,104 m. In order to reach this section of the motorway, 9.8 km. along the former N-VI had to be travelled, including very steep access ramps to the pass from Leon. With the new works, the maximum slopes were 5% and a project speed of 120 Km/h was achieved along the entire route.

Amongst other tasks, the works involved the construction of 6 large viaducts, some over 100 metres high; the extension and rehabilitation of two previously existing viaducts (Ruitelan and Las Lamas); the execution of many walls, road cuts and embankments, some very high and difficult in technical terms; the conditioning and improvement of 7 km along the former N-VI; and the construction of an overpass, 4 underpasses and various different paths under the viaducts. Due to the narrow width of the valley and steep slopes on the sides, the roadways were separately built along 6 km of the 8.5 km section. As a result, their height often varied by 30 metres.

From an environmental point of view, the section has the necessary means to protect the area's water resources and fauna, to provide protection against erosion and to enable environmental restoration and the incorporation of the landscape and surroundings thanks to: the construction of earth dams to protect the embankments, systems to intercept polluting waste produced by the motorway drainage system, replanting of banks, construction of environmentally-friendly walls, andr the implementation of an environmental surveillance plan during execution of the works, including the necessary archaeological supervision.