Widening of the bridge over the Rande Strait, Spain

The widening of the bridge over the Rande strait is the first long span cable-stayed bridge widened in the world, being a unique milestone in the field of Structural Engineering. Its innovative design solves the functional problem proving a notary increase of the highway capacity while maximizing the use of the structural strength of the existing bridge as well as improving its dynamic behaviour. Thanks to a carefully planned methodology, the construction have been accomplished without affections to both the traffic on the existing bridge and the natural environment of Vigo estuary in a record time of 14 months for the on-site erection.

 Type of structure:  Widening of a cable-stayed bridge
 Date of completion:  December, 2017
 Location:  Rande Strait, Spain
 Ministerio de Fomento (Spanish Road Authority)
 Concessionaire:  Autopistas del Atlántico, C.E.S.A.
 Structural Design:          MC2 Estudio de Ingenieria S.L. and Dr.Manuel Juliá Vilardell
 General Contractor:  JV Dragados + Grupo Puentes

The Atlantic Motorway, AP-9, is the main North–South road route in Galicia (Spain) and crosses the Vigo estuary by means of a 400-m span cable-stayed bridge over the Rande Strait. This bridge was built between 1973 and 1977, and was opened to traffic in 1981. In 2006, the average daily traffic reached 55.000 vehicles, close to its effective capacity and therefore resulted in frequent traffic congestion conditions. In order to increase the bridge’s traffic capacity, several studies were carried out considering different alternatives. Taken into account the technical, aesthetic and economic aspects, the most favourable solution found and developed was a widening project consisting of two new external decks positioned along both the outer sides of the existing deck next to the main piers. This system allowed bridge-widening work without both interrupting the traffic on the existing bridge and affecting the Vigo estuary—a very valuable zone from a natural environmental and landscape perspective. These restrictions had a critical impact in the building process.