Consulting and assistance services for the supervision of the construction works of Highway A-63 (Oviedo-La Espina) and Road N-634 (San Sebastián-Santiago de Compostela) Section: Grado (O)-Doriga, from km 2+500 to 6+500

The main trunk of the highway has a length of 4,218 m and runs from east to west, making two turns. First, it turns to the left up to El Fresco Tunnel, a two-tube tunnel with one tube per carriageway. The left one has a length of 949 m (904 m of excavated tunnel + 45 m of cut-and-cover tunnel) and the right one has a length of 923 m (878 m of excavated tunnel and 45 m of cut-and-cover-tunnel). The horizontal alignment has a constant radius and a constant gradient of 0.6%.

Doriga Junction is located at the end of this road section: a trumpet junction intended to access SL-9 road by means of a roundabout at the end of the bidirectional branch line of the junction. The route also includes an access to AS-15 road, with a length of 720 m.

The works comprised 9 structures (3 overpasses and 6 underpasses). The overpasses were built with post-tensioned slabs and a prestressed lightweight concrete deck with 6 double T-beams, 2 m thick. The underpasses are frame-type structures with 7 x 5 m clearance, with the exception of two: one of them is composed of an arch span and a deck built with double T-beams; the other is made of a reinforced concrete vault with a 7 m horizontal clearance.

The project included the construction of 17 culverts of different sizes and installation of control and safety systems in the tunnel.


Demarcación de Carreteras del Estado en Asturias (Demarcation of State Roads in Asturias). Ministerio de Fomento (Ministry of Development)

Project Dates

2006 – 2009

Project Figures

Contract Value:
1,196,548.00 €