Alamillo Bridge and Cartuja Viaduct
Seville, Spain
1987 - 1992

Photos courtesy Santiago Calatrava archives

The Expo Œ92 World Fair provided the authorities of Seville with an opportunity to improve the infrastructure of the city and its surrounding areas in the Province of Andalusia. This initiative included the provision of better road connections to neighboring towns, a ring road for Seville, and eight new bridges over the Guadalquivir river.

The Alamillo Bridge spans 200 meters over the section of the river known as the Meandro San Jerónimo and is connected to a viaduct for automobiles, bicyclists and pedestrians that crosses La Cartuja island.

The bridge is supported by thirteen pairs of stay cables from a 142 meter high pylon inclined at an angle of 58 degrees. The pylon was constructed by lifting segments of the steel shell into place with a large, high-capacity crane, then welding them together and filling them with reinforced concrete.

The core of the tower contains a service stair to the top.  The weight of the pylon is sufficient to counterbalance the deck, and backstays are thus not required. This new type of cable-stayed bridge, which substitutes the weight of an inclined pylon for one set of stay cables, creates a dialogue of balance between pylon and deck.

The bridge deck consists of an hexagonal, steel box beam spine, to which the stay cables are attached. The steel wings, supporting the deck to either side, are cantilevered off this spine, whose 3.75 meter wide top side, elevated some 1.6 meters above road level, serves as an elevated footway and cycle route between the separated traffic lanes. The box girder and cantilevered road deck elements were initially constructed on continuous false work, supported on the mostly dry riverbed.

The La Cartuja Viaduct was built as a gateway to the north entrance of the Expo Œ92 site. It is a continuous structure with a vaulted underside and overlapping levels. Each of its two 10 meter (33 feet) carriageways cantilevers 5 meters away from the top of the structure, providing shade for pedestrians on the cantilevered promenade decks below.

The structure receives light through three continuous rows of circular light wells; one along the crown of the vault between the two carriageways and the other two at the sides, between the carriageway and the promenades.

The Alamillo site is unusual in that the same river is crossed twice.

Client: Regional Government of Andalusia, Seville. Total length of bridge 200 meters  (655 feet) Length of viaduct: 526.5 meters (1,727 feet).