25 de Abril Bridge

The 25 de Abril Bridge (Portuguese: Ponte 25 de Abril, 25th of April Bridge, Portuguese pronunciation: [ˈpõt(ɨ) ˈvĩt i ˈsĩku ðɨ ɐˈβɾiɫ]) is a suspension bridge connecting the city of Lisbon, capital of Portugal, to the municipality of Almada on the left (south) bank of the Tagus river. It was inaugurated on August 6, 1966. It is often compared to the Golden Gate Bridge in San Francisco, US, because they are both suspension bridges of similar color. It was built by the American Bridge Company which constructed the San Francisco–Oakland Bay Bridge, but not the Golden Gate. With a total length of 2,277 metres (7,470 ft), it is the 40th largest suspension bridge in the world. The upper deck carries six car lanes, while the lower deck carries a double track railway electrified at 25 kV AC; the train platform was added in 1999. From 1966–1974, the bridge was named Salazar Bridge (Ponte Salazar) in honor of Portuguese Prime Minister António de Oliveira Salazar, who ordered its construction. After the Carnation Revolution which overthrew the remnants of Salazar's dictatorship, the bridge was renamed for April 25, the date of the revolution. It is also sometimes called the Tagus River Bridge or in Portuguese Ponte sobre o Tejo ("bridge over the Tagus").[1][2]

Ponte 25 de Abril
View with the Christ the King Sanctuary
Coordinates38.690066°N 9.177017°W / 38.690066; -9.177017
CarriesSix road lanes of  IP 7 
Two railway tracks of Linha do Sul
CrossesTagus River
LocaleLisbon (right/North bank)
Pragal (left/South bank)
Official namePonte 25 de Abril
Other name(s)Ponte Salazar (before 1974)
Tagus River Bridge
Maintained byLusoponte
Characteristics
DesignSuspension
Total length18 kilometres (11 mi)
Longest span1,012.88 m
Clearance below70 m at mean high water
History
Opened6 August 1966
Statistics
Daily traffic150,000 cars
157 trains
Toll1.85 € (northbound only)

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 Montijo (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 Xira, 35 kilometres (22 mi) 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 King (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. The American School of Lisbon was founded at this time to educate the children of the American engineers brought to Portugal to work on the bridge's construction.[3]

Construction began on 5 November 1962. Forty-five months later (six months ahead of schedule) the bridge was inaugurated on 6 August 1966. 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 Lisbon, Cardinal Manuel Gonçalves Cerejeira. The bridge was named Salazar Bridge (Ponte Salazar), for Prime Minister Salazar.[4]

United States Steel International, Inc. based in New York, was prime contractor for the bridge. Morrison-Knudsen of Portugal, Ltd., an American firm based in Boise, Idaho was U.S. Steel's principal associate. Morrison-Knudsen had previously worked on the San Francisco Bay Bridge. Steinman, Boynton, Gronquist and London of New York, and Tudor Engineering Company of San Francisco designed the bridge.[5] The steel was imported from the US. 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 2.2 billion Portuguese escudos, or US$32 million (US$225 million in 2011 adjusted for inflation).

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 (230 ft) above water, started carrying 4 car lanes, two in each direction, with a dividing guardrail. On 23 July 1990, this guardrail was removed and a fifth, reversible lane was created. On 6 November 1998, the side walls were extended and reinforced to make space for the present six lanes. Cars crossing the bridge make a peculiar hum - listen (59s) - as the two inner lanes are relatively slippery metallic platforms instead of asphalt.

Since 30 June 1999, the lower platform has carried a double track railway. 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 railway had been part of the initial design, but was eliminated for economy, so the initial structure was lightened. The 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 railway, 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, presently the plan has been dropped due to Portugal's budget constraints.

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.

Normally, pedestrians cannot walk across the bridge, but every year there is a half-marathon that starts on the south bank and finishes in the north bank (Belem).

Recently an observation deck was built allowing people to go to the platform.

Tolls
South view of 25 de Abril Bridge with the Sanctuary of Christ the King and Almada.

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. The tolls have become a source of political dispute in recent years.

When opened, one had to park their car and walk to buy the toll ticket costing 20 escudos. On 14 June 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 into private concession for 40 years from 1 January 1996. The concessionaire was Lusoponte, a private consortium formed to build the Vasco da Gama Bridge at no 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, an event which made the then right-wing Government highly unpopular and which many believe led to a centre-left win in the 1995 general elections. The toll is set at €1.85 for passenger cars (as of March 2020), northbound (into Lisbon). There is no toll southbound, and until 2010, no tolls were collected during the month of August. From 2011 on, the Portuguese Government abolished this exception and ordered tolls to be charged also during this month, in order to help the efforts to reduce the budget deficit.

Assuming that no legal changes happen in between, the concession will end on 24 March 2030, after which the Bridge will again be State-managed.[6][7]

Design
The 25 de Abril Bridge at night.

The 25 de Abril Bridge is based in part on two San Francisco Bay Area bridges: its paint is the same International Orange as the famous Golden Gate Bridge; and its design is similar to that of the San Francisco–Oakland Bay Bridge. Both the Bay Bridge and the 25 de Abril Bridge were built by the same company.[8] 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 Bridge in Edinburgh.

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 US. Today it is the 27th largest suspension bridge in the world.

Numbers

As of 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:

  • 1,012.88 m (3,323.1 ft) – length of main span
  • 2,277.64 m (7,472.6 ft) – length of truss
  • 70 m (229.7 ft) – height from water to upper platform
  • 190.47 m (624.9 ft) – height of main towers (seventh tallest structure in Portugal)
  • 58.6 cm (23.1 in) – diameter of each of the two sets of main cables
  • 11,248 – number of steel wire strand cables, each 4.87 mm (0.192 in) in diameter, in each set of main cables
  • 54,196 km (33,676 mi) – length of steel wire strand cables making up the two sets of main cables
  • 79.3 m (260.2 ft) – depth (below water-level) of the foundation of the south pillar
  • 30 km (19 mi) – length of access roads
  • 32 – viaducts in the access roads
View from Almada.
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See also

References
  1. "Tagus River Bridge (Lisbon, 1966)". Structurae.
  2. "Tagus River Bridge diary / 1962-1967". oac.cdlib.org.
  3. "Carlucci American International School of Lisbon: St. Columban's Era". www.caislisbon.org.
  4. "Use of Special Techniques in Refurbishment", by J-P. Muzeau, in Refurbishment of Buildings and Bridges (Springer, 2014) p305
  5. Morrison, H.W. “Chairman’s Memo: Bridge Opens New Vistas for Portugal.” The Em Kayan, October 1966.
  6. "Vasco da Gama Bridge — Funding". Lusoponte. Archived from the original on 11 February 2016. Retrieved 30 November 2016.
  7. "Infraestruturas Rodoviárias > Rede Rodoviária > Concessões" [Road infrastructures > Road network > Concessions] (in Portuguese). Instituto da Mobilidade e dos Transportes. Archived from the original on 2016-11-30. Retrieved 30 November 2016.
  8. "Frequently Asked Questions about the Golden Gate Bridge". Golden Gate Bridge. Archived from the original on 2015-08-10. Retrieved 2020-06-12.

Bibliography

RODRIGUES, Luís Ferreira (2016). A ponte inevitável: a história da Ponte 25 de Abril. Lisboa: Guerra e Paz

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