Widening of the Cable-Stayed Bridge over the Rande Strait, Spain

The Atlantic Motorway 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 47 000 vehicles, close to its effective capacity, which therefore, resulted in frequent traffic congestion. A widening project to increase the original four lanes up to six lanes has been developed by the authors in order to increase the bridge's traffic capacity without constructing a new bridge. Special attention has been paid to designing a structural solution that, in addition to having a moderate cost, could be built without interrupting the traffic on the existing bridge. Besides, considering the densely populated area in which the bridge is located, the designed solution tries not to adversely affect the visual appearance of the bridge. The structural widening solution consists of two new external decks located along both sides of the existing deck next to the main piers. These new decks are suspended from the piers by means of two new families of stays and a couple of steel box elements that transfer the loads from the anchorages to the existing main concrete piers. The new decks are also supported from the existing deck by means of light transversal trusses.