“Vila Pouca de Aguiar” viaduct The viaduct crosses the valley of “Vila Pouca de Aguiar”, at a maximum height of 90m, and the “Corgo” River and, also, the EN2 (National Road 2). This is one of the most sensitive sections of the A24 motorway, for which some pioneering solutions in terms of nature conservation were designed, with the need for the viaduct arising from a requirement not to disturb a Natura 2000 site of great natural richness where several endangered species procreate, including the Iberian wolf.

The superstructure, totally continuous, is composed by two parallel box girder decks, 5m apart with 17 spans and a total length of 1348m.

The prestressed concrete decks were entirely cast “in situ”. Six pairs of travellers were used for the construction of the 2x5 central spans of the viaduct, with 130m each, by the balanced cantilever method in 5.0m segments. Two self-launching girders were used, one in each extremity of the structure for the construction of the 2x9 60m spans.

The central piers reach a maximum height of 80m and their tubular shafts have a constant rectangular cross-section in the upper part. In order to provide the necessary widening and rigidity towards the base, the four corners have variable dimensions. The lateral piers are similar to the central piers but are smaller and with a constant cross-section. The decks are monolithic with central piers and are supported by pot-bearings at the other piers. The foundations are laid directly onto altered granite formations.

The viaduct’s construction began in September 2005 and was completed in June 2007.