Southern metropolitan bypass of Bilbao

The Southern metropolitan bypass is a motorway acting as a beltway for Bilbao. It is the largest investment in road infrastructure in the Basque Country and includes the largest road cavity in Europe. The sections involved in the contract covered a length of trunk road of 10.5 km. Most of this (7.4 km) runs through 5 two- and three-lane tunnels. Other actions include the construction of 5 viaducts and two junctions.

The most iconic structure is the Gorostiza viaduct with a single 130-metre span and no intermediary support. The contract covers three phases; drafting and supervision of the construction designs; support to Interbiak in public information, obtaining the Environmental Impact Declaration, compulsory purchase and study of contractors’ tenders; finally, the third phase consisted of monitoring execution of the work, and technical assistance to site management.