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The 25 de Abril Bridge (Ponte 25 de Abril "25th of April Bridge", ) is a suspension bridge connecting the city of Lisbonmarker, capital of Portugalmarker, to the municipality of Almadamarker on the left bank of the Tejo rivermarker. It was inaugurated on August 6 1966 and a train platform was added in 1999. Because of its similar coloring, it is often compared to the Golden Gate Bridgemarker in San Franciscomarker, USAmarker. In fact, it was built by the same company (American Bridge Company) that constructed the San Francisco-Oakland Bay Bridge and not the Golden Gate, also explaining its similarity in design. With a total length of 2,277 m, it is the 20th largest suspension bridge in the world. The upper platform carries six car lanes, the lower platform two train tracks. Until 1974, the bridge was named Salazar Bridge.

History

Construction

From the late 19th century there had been proposals to build a bridge for Lisbon. In 1929 the idea advanced as a Portuguese engineer and entrepreneur, António Bello requested a Government concession for a railway crossing between Lisbon and Montijomarker (where the Vasco da Gama Bridge, the second bridge serving Lisbon, was later built in 1998). As a result, the Minister of Public Works, Duarte Pacheco, created a commission in 1933 to analyse the request. The commission reported in 1934, and proposed building a road and rail bridge. Bids were obtained. However, this proposal was subsequently put aside in favour of a bridge crossing the river at Vila Franca de Xiramarker, 35 km north of Lisbon.

In 1953 a new Government commission started working and recommended building the bridge in 1958, choosing the southern anchor point adjacent to the recently built monument to Christ the Kingmarker (Cristo-Rei). In 1959 the international invitation to tender for the project received four bids. In 1960 the winner was announced as a consortium headed by the United States Steel Export Company, which had submitted a bid in 1935.

Construction began on November 5 1962. 45 months later the bridge was inaugurated on August 6 1966, six months ahead of schedule. Presiding at the ceremony was the President of Portugal, Admiral Américo Thomaz. Also present were the Prime-Minister, António de Oliveira Salazar, and the Patriarch of Lisbonmarker, Cardinal Manuel Gonçalves Cerejeira. The bridge was named Salazar Bridge (Ponte Salazar), in honour of the Prime-Minister.

The bridge was built by the American Bridge Company, part of the winning consortium and aided by eleven local companies. The steel was imported from the USA. Four workers lost their lives, out of a total of 3,000 who worked on the site. Construction took a total of 2,185,000 man-hours of work. The total cost of the bridge came to 2,200,000,000 Portuguese escudos, or US $ 32 million (US $201 million in 2006 adjusted for inflation).

25 de Abril Bridge.


Soon after the Carnation Revolution in 1974, the bridge was renamed the 25 de Abril Bridge, the day the revolution had occurred. A symbol of those times was captured on film, with citizens removing the big "Salazar" brass sign from one of the main pillars of the bridge and painting a provisional "25 de Abril" in its place.

Expansion

The upper platform, running 70 m above water, started carrying 4 car lanes, two in each direction, with a dividing rail. On July 23 1990, this rail was removed and a fifth reversible lane was created. On November 6 1998 the side walls were extended and reinforced to make space for the present six lanes.

Cars crossing the bridge make a peculiar hum - - as two of the lanes are metallic platforms instead of asphalt.

Since June 30 1999, the lower platform carries two railroad tracks. To accommodate this, the bridge underwent extensive structural reinforcements, including a second set of main cables, placed above the original set, and the main towers were increased in height. The rail line had been part of the initial design, but was eliminated for economy, and the initial structure had been lightened. Original builder American Bridge Company was called again for the job, performing the first aerial spinning of additional main cables on a loaded, fully operational suspension bridge.

Traffic soon increased well beyond predictions, and has remained at maximum capacity despite the enlargement from four to six lanes, the addition of the rail line, and the building of a second bridge serving Lisbon, the Vasco da Gama Bridge. A third bridge has been on and off Government plans for some time.

Several movies have been filmed on the bridge, including some scenes in the 1969 James Bond film On Her Majesty's Secret Service when James Bond is in a car with Marc Ange Draco's henchmen and they drive across a bridge, and the bridge is featured near the end of the movie when Bond marries Tracy and drives with her in Bond's Aston Martin across the bridge again.

Tolls

The bridge was projected to have paid all debt in 20 years, and to become toll-free (or reduced toll) after that period. However the Government kept charging tolls well beyond the 20 year period, until it gave the concession to Lusoponte, creating a monopoly of the Tagus crossing in Lisbon. As such, the bridge has always required a toll, first in both directions and from 1993 northbound only, with the toll plaza situated on the south bank of the Tagus river.

When opened one had to park their car and walk to buy the toll ticket costing 20 escudos. In June 14 1994, the Government, which ran the bridge at the time, raised the toll by 50% (100 to 150 escudos), to prepare to give the bridge in concession for 40 years from January 1 1996. The concessionaire was Lusoponte, a private consortium formed to build the Vasco da Gama Bridge at zero-cost to the public finances in exchange for tolls from both bridges. As a result, a popular uprising led to road blockades of the bridge and consequent police charges, weakening the Government. As of 2009, the toll is set at € 1.35 for passenger cars, northbound (into Lisbon). There is no toll southbound and no toll either way during August.

Design

The 25 de Abril Bridge is based on the San Francisco – Oakland Bay Bridgemarker [SFOBB] near the Golden Gate Bridgemarker in San Franciscomarker, USAmarker. Both SFOBB and the 25 de Abril Bridge were built by the same company. The American Society of Civil Engineers says that "Like its sister bridge, the SFOBB in San Francisco, the Tagus River Bridge is located in an area with a long history of earthquakes" and seismic data had to be taken into account in its construction. Another sister bridge is the Forth Road Bridgemarker in Edinburghmarker.

Upon completion the bridge had the longest suspended span and the longest main span in Continental Europe, the world's longest continuous truss, and the world's deepest bridge foundation. It was the fifth largest suspension bridge in the world, the largest outside the USAmarker. Today it is the 20th largest suspension bridge in the world.

Numbers

In 2006 a daily average of 150,000 cars cross the bridge, including 7,000 on the peak hour. Rail traffic is also heavy, with a daily average of 157 trains. In all, around 380,000 people cross the bridge daily (190,000 if considering return trips).

Other numbers:
  • 1012,88 m - length of main span
  • 2277,64 m - length of truss
  • 70 m - height from water to upper platform
  • 190,47 m - height of main towers (second tallest structure in Portugal)
  • 58,6 cm - diameter of each of the two sets of main cables
  • 11,248 - number of steel wire strand cables, each 4,87 mm in diameter, in each set of main cables
  • 54,196 km - length of steel wire strand cables making up the two sets of main cables
  • 79,3 m - depth (below water-level) of the foundation of the south pillar
  • 30 km - length of access roads
  • 32 - viaducts in the access roads


Partial source: TV documentary aired on August 6 2006 on Portuguese station RTP1.

View from Belém



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