Widening of the Cable-Stayed Bridge Over the Rande Strait in Spain

The Atlantic Motorway, AP-9, crosses the Vigo estuary in Spain by means of a 400 m span cable-stayed bridge with a composite deck over the Rande Strait. This bridge was built between 1973 and 1977, and 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. To increase the bridge's traffic capacity, feasibility studies were carried out. After technical, aesthetic and economic comparative analyses, the most favourable solution found was a widening project. The widening solution consists of two new external composite decks positioned along both the outer sides of the existing deck next to the main piers. This system, a worldwide pioneer, will allow bridge-widening works without either interrupting the traffic on the existing bridge or affecting the Vigo estuary, a very valuable zone from a natural environmental and landscape perspective.