Vasco da Gama Bridge
Encyclopedia
The Vasco da Gama Bridge ˈvaʃku dɐ ˈɡɐmɐ) is a cable-stayed bridge
flanked by viaduct
s and rangeviews that spans the Tagus River
near Lisbon
, capital of Portugal
. It is the longest bridge in Europe
(including viaducts), with a total length of 17.2 km (10.7 mi), including 0.829 km (0.5 mi) for the main bridge, 11.5 km (7.1 mi) in viaducts, and 4.8 km (3.0 mi) in dedicated access roads. Its purpose is to alleviate the congestion on Lisbon's other bridge (25 de Abril Bridge
), and to join previously unconnected motorways radiating from Lisbon.
The bridge was opened to traffic on 29 March 1998, 18 months after construction first began, just in time for Expo 98, the World's Fair that celebrated the 500th anniversary of the discovery by Vasco da Gama
of the sea route from Europe to India
.
Bridge sections
The bridge has a life expectancy of 120 years, having been designed to withstand wind speeds of 250 km/h (155.3 mph) and hold up to an earthquake 4.5 times stronger than the historical 1755 Lisbon earthquake
(estimated at 8.7 on the Richter scale
). The deepest foundation piles, up to 2.2 m (7.2 ft) in diameter, were driven down to 95 m (312 ft) under mean sea level. Due to the bridge's length, it was necessary to take the Earth
's curvature into account to site the piers correctly, otherwise a deviation of 80 cm (31 in) would be apparent at either end of the bridge. Environmental pressure throughout the project resulted in the left-bank viaducts being extended inland to preserve the marshes underneath, as well as the lamp posts throughout the bridge being tilted inwards so as not to cast light on the river below.
The cost of the bridge came at zero to the State, as it was built in the BOT (build-operate-transfer) system by Lusoponte, a private consortium which got a 40-year concession on the tolls of both Lisbon bridges. Lusoponte's capital is 50.4% from Portuguese companies, 24.8% French and 24.8% British.
As of 2009, the toll is €
2.40 per passenger car (up to €10.80 per truck) northbound (into Lisbon). There is no toll for southbound traffic.
Cable-stayed bridge
A cable-stayed bridge is a bridge that consists of one or more columns , with cables supporting the bridge deck....
flanked by viaduct
Viaduct
A viaduct is a bridge composed of several small spans. The term viaduct is derived from the Latin via for road and ducere to lead something. However, the Ancient Romans did not use that term per se; it is a modern derivation from an analogy with aqueduct. Like the Roman aqueducts, many early...
s and rangeviews that spans the Tagus River
Tagus
The Tagus is the longest river on the Iberian Peninsula. It is long, in Spain, along the border between Portugal and Spain and in Portugal, where it empties into the Atlantic Ocean at Lisbon. It drains an area of . The Tagus is highly utilized for most of its course...
near Lisbon
Lisbon
Lisbon is the capital city and largest city of Portugal with a population of 545,245 within its administrative limits on a land area of . The urban area of Lisbon extends beyond the administrative city limits with a population of 3 million on an area of , making it the 9th most populous urban...
, capital of Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
. It is the longest bridge in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
(including viaducts), with a total length of 17.2 km (10.7 mi), including 0.829 km (0.5 mi) for the main bridge, 11.5 km (7.1 mi) in viaducts, and 4.8 km (3.0 mi) in dedicated access roads. Its purpose is to alleviate the congestion on Lisbon's other bridge (25 de Abril Bridge
25 de Abril Bridge
The 25 de Abril Bridge is a suspension bridge connecting the city of Lisbon, capital of Portugal, to the municipality of Almada on the left bank of the Tejo river. It was inaugurated on August 6, 1966 and a train platform was added in 1999...
), and to join previously unconnected motorways radiating from Lisbon.
The bridge was opened to traffic on 29 March 1998, 18 months after construction first began, just in time for Expo 98, the World's Fair that celebrated the 500th anniversary of the discovery by Vasco da Gama
Vasco da Gama
Vasco da Gama, 1st Count of Vidigueira was a Portuguese explorer, one of the most successful in the Age of Discovery and the commander of the first ships to sail directly from Europe to India...
of the sea route from Europe to India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
.
Description
The bridge carries six road lanes, with a speed limit of 120 km/h (74.6 mph), the same as motorways, except on one section which is limited to 100 km/h (62.1 mph). On windy, rainy, and foggy days, the speed limit is reduced to 90 km/h (55.9 mph). The number of road lanes will be enlarged to eight when traffic reaches a daily average of 52,000.Bridge sections
- North access roads
- North viaduct - 488 m (1,601 ft)
- Expo viaduct - 672 m (2,205 ft); 12 sections
- Main bridge - main span: 420 m (1,378 ft); side spans: 203 m (666 ft) each (total length: 829 m (2,720 ft)); cement pillars: 150 m (492 ft)-high; free height for navigation in high tides: 45 m (148 ft);
- Central viaduct - 6.351 m (20.84 ft); 80 pre-fabricated sections 78 m (256 ft)-long; 81 pillars up to 95 m (312 ft)-deep; height from 14 m (46 ft) to 30 m (98 ft)
- South viaduct - 3.825 m (12.55 ft); 45 m (148 ft) sections; 84 sections; 85 pillars
- South access roads - 3.895 m (12.78 ft); includes the toll plaza (18 gates) and two service areas
Construction and cost
The project was split in four parts, each one built by a different company, and supervised by an independent consortium. There were up to 3,300 workers simultaneously on the project, which took 18 months of preparation and another 18 months of construction.The bridge has a life expectancy of 120 years, having been designed to withstand wind speeds of 250 km/h (155.3 mph) and hold up to an earthquake 4.5 times stronger than the historical 1755 Lisbon earthquake
1755 Lisbon earthquake
The 1755 Lisbon earthquake, also known as the Great Lisbon Earthquake, was a megathrust earthquake that took place on Saturday 1 November 1755, at around 9:40 in the morning. The earthquake was followed by fires and a tsunami, which almost totally destroyed Lisbon in the Kingdom of Portugal, and...
(estimated at 8.7 on the Richter scale
Richter magnitude scale
The expression Richter magnitude scale refers to a number of ways to assign a single number to quantify the energy contained in an earthquake....
). The deepest foundation piles, up to 2.2 m (7.2 ft) in diameter, were driven down to 95 m (312 ft) under mean sea level. Due to the bridge's length, it was necessary to take the Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
's curvature into account to site the piers correctly, otherwise a deviation of 80 cm (31 in) would be apparent at either end of the bridge. Environmental pressure throughout the project resulted in the left-bank viaducts being extended inland to preserve the marshes underneath, as well as the lamp posts throughout the bridge being tilted inwards so as not to cast light on the river below.
The cost of the bridge came at zero to the State, as it was built in the BOT (build-operate-transfer) system by Lusoponte, a private consortium which got a 40-year concession on the tolls of both Lisbon bridges. Lusoponte's capital is 50.4% from Portuguese companies, 24.8% French and 24.8% British.
As of 2009, the toll is €
Euro
The euro is the official currency of the eurozone: 17 of the 27 member states of the European Union. It is also the currency used by the Institutions of the European Union. The eurozone consists of Austria, Belgium, Cyprus, Estonia, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg,...
2.40 per passenger car (up to €10.80 per truck) northbound (into Lisbon). There is no toll for southbound traffic.
External links
- Portal das Nações Discover the Ponte Vasco da Gama
- BBC news story of bridge opening
- Flickr photos of bridge