Vasco da Gama Bridge
|This article relies on references to primary sources. (March 2011)|
|Vasco da Gama Bridge|
|Official name||Ponte Vasco da Gama|
|Carries||Six road lanes|
|Locale||Sacavém, north of Lisbon (right bank)
Municipality of Alcochete (left bank)
|Total length||17.2 km (10.7 mi)|
|Width||30 m (98 ft)|
|Height||155 metres (509 ft) (pylon)|
|Longest span||420 m (1,378 ft)|
|Toll||€2.60 per passenger car (up to €10.80 per truck) northbound o|
The Vasco da Gama Bridge (Portuguese: Ponte Vasco da Gama; pronounced: [ˈpõt(ɨ) ˈvaʃku dɐ ˈɡɐmɐ]) is a cable-stayed bridge flanked by viaducts and rangeviews that spans the Tagus River in Parque das Nações in 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.
Construction began on February 1995; the bridge was opened to traffic on 29 March 1998, 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.
The bridge carries six road lanes, with a speed limit of 120 km/h (75 mph), the same as motorways, except on one section which is limited to 100 km/h (60 mph). On windy, rainy, and foggy days, the speed limit is reduced to 90 km/h (56 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 or 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 $1.1bn 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 18 months of construction. The financing is via a build-operate-transfer system by Lusoponte, a private consortium which receive the first 40-year of tolls of both Lisbon bridges. Lusoponte's capital is 50.4% from Portuguese companies, 24.8% French and 24.8% British. As of August 2013, the toll is €2.60 per passenger car (up to €11.55 per truck) northbound (into Lisbon). There is no toll for southbound traffic.
The bridge has a life expectancy of 120 years, having been designed to withstand wind speeds of 250 km/h (155 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. 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.
- (Portuguese) www.civilium.net
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