The construction of Vasco da Gama Bridge over the river Tagus by Lusoponte has passed into the annals of the history of civil engineering as one of the largest and most successful projects of the 20th Century.
This Project gained international recognition when it was awarded first prize by the prestigious Ibero-Americana Institution of Architecture and Civil Engineering in the year 2000.
The construction of the bridge was divided into seven sections:
1 - Sacavém and EN10 Variant Interchanges
Two interchanges on the north side of the Tagus link with the A1 motorway to the north, the CRIL and the EN 10 Variant, which provide access to Lisbon and the “Parque das Nações”.
2 - North Viaduct
A 488 m long viaduct which spans the main railway line and several local access roads, with a variable deck width to accommodate the slip roads.
3 - Expo Viaduct
A 672 m long viaduct comprising pre-cast concrete segments and placed in an inner way on each side of the piers.
4 - Main Bridge
The Main Bridge it is a spectacular concrete structure as the deck it is stayed to main pylons.
4.1 - Main Bridge North Pylon
Its central span is of 420 m and the side spans of 203 m. The central pylons are 150 m high and the deck gives a clearance of 47 m above water level on the navigation channel called North Channel.
4.2 - Stay Bridge Main span 420m
The deck is a mix-structure composed with concrete slabs laying on steel crossbeams casted on two side concrete beams where the stays are linked to the pylons.
The H-shaped north and south pylons, stand on foundations designed to withstand impact from a 30.000 tonne ship travelling with a speed cruise of 12 nuts.
Each foundation of these pylons are casted on 44 precast piles with 2,2 m diameter which are bored up to 90 m.
5 - Central Viaduct
The construction of the 6,351 m Central Viaduct was carried out using double pre-cast units with 78 m long weighing 2,200 tonnes placed on 81 piers. The foundation of each pair of piers are cast on 8 driven piles, with 1,7 m diameter reaching sometimes 65 m deep on the river bed.
5.1 - Central Viaduct
The deck is less than 14 m above water level for most of its length but rises to 30 m over two navigation channels, the Barcas Channel and the Samora Channel with spans of 130 m to accommodate medium sized vessels.
The piers located on these two channels were also designed to withstand ship impact.
Five of the deck sections have wider edges to provide for emergency vehicle parking.
A huge pre-casting yard at Seixal, 22 kms downstream from the bridge, was used to manufacture concrete pre-cast units for this viaduct. The deck sections were made in eight pieces, stitched into 78 m long beams and then it was applied the use of pre-stressed cables.
5.2 - Seixal pre-cast yard
The deck beams where then transported to the site on the giant crane vessel Rambiz. The yard worked to a schedule, producing one beam every two days.
6 - South Viaduct
The South Viaduct with 3.825 metres long consists in a twin deck with 45 metres spans, which were cast in situ using twin launching girders.
The 85 groups of 4 piers of this Viaduct are cast partially on land and partially on marine driven piles.
This Viaduct land section crosses the Samouco Salt Pans an environment area for birds.
6.1 - South Viaduct Samouco Salt Pans
This Viaduct was constructed on a temporary embankment, which was removed after works conclusion.
7 - South Access
The 3,9 km South Access links the Vasco da Gama Bridge with the South Interchange mainly through agricultural land. The most closed local links are Setubal (A12 motorway) and with Alcochete and Montijo (Coina Ring).
The Toll Plaza is located about halfway along this stretch south/north bound and incorporates 12 booths with cash or automatic systems means of payment. On both sides of the crossing the driver can find a fully service area, close to the South Viaduct.