25 de Abril Bridge
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 View from Cristo-Rei (south bank) |
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| Official name | Ponte 25 de Abril (former Ponte Salazar) |
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| Carries | Six road lanes Two train tracks |
| Crosses | Tagus river |
| Locale | Lisbon, Portugal (right bank) Municipality of Almada (left bank) |
| Maintained by | Lusoponte [1] |
| Design | Suspension |
| Longest span | 1,012.88 m |
| Total length | 2,277.64 m |
| Clearance below | 70 m at mean higher high water |
| AADT | 150,000 cars 157 trains |
| Opening date | August 6, 1966 |
| Toll | 1.20 euro (northbound) |
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The 25 de Abril Bridge (translation: 25th of April Bridge, in Portuguese: Ponte 25 de Abril, pron. IPA: ['põt(ɨ) 'vĩt(ɨ) 'sĩku dɨ ɐ'bɾiɫ]) is a suspension bridge connecting the city of Lisbon, capital of Portugal, to the left bank of the Tagus river (municipality of Almada). It was inaugurated on August 6, 1966 and enlarged in 1999. It is often compared to the Golden Gate Bridge in San Francisco, USA, due to their similarities and same construction company. With a total length of 2,277 m, it is the 17th largest suspension bridge in the world. The upper platform carries six car lanes, the lower platform two train tracks.
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[edit] History
Since the late 19th century there had been a series of offers to project a bridge for Lisbon. However, it was only in 1929 that the idea was definitely pushed on as Portuguese engineer and entrepreneur António Belo requested a Government concession for a train crossing between Lisbon and Montijo (where the Vasco da Gama Bridge, the second bridge serving Lisbon, eventually was built in 1998). This had the effect of forcing the Minister of Public Works Duarte Pacheco to name a commission in 1933 to analyze the request. In 1934, the result was the proposal to build a car-and-train bridge; bids even started to be gathered. However, this proposal was put aside in favor of a bridge which was built in Vila Franca de Xira, 35 km north of Lisbon.
In 1953, a new Government commission started working and again recommended, in 1958, to build the bridge, choosing the south anchor point right next to the recently-built monument to Christ the King (Cristo-Rei).
The process would now proceed swiftly. In 1959, the international open bid for the project and construction received four bids. In 1960, the winner was announced as a consortium headed by the United States Steel Export Company, which had also submitted a bid in 1935.
On November 5, 1962, construction began. 45 months (less than four years) 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 Lisbon, Cardinal Manuel Gonçalves Cerejeira. The bridge was christened Salazar Bridge (Ponte Salazar), in honor of the Prime-Minister.
The bridge was built by the American Bridge Company, part of the winning consortium, with the help of eleven local companies. All the steel was imported from the USA. Four workers lost their lives, out of 3,000 that worked simultaneously on the site, for 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).
At the time of its 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 USA. Today, it is the 17th largest suspension bridge in the world.
The 25 de Abril Bridge is often compared to the Golden Gate Bridge in San Francisco, USA and not just because it was built by the same company. The American Society of Civil Engineers says that "Like its sister bridge, the Golden Gate 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.
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 populars 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.
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; finally, on November 6, 1998 the side walls were extended and reinforced to make way for the present six lanes.
Cars crossing the bridge make a peculiar hum - listen (59s) - as two of the lanes are metallic platforms instead of asphalt.
The bridge has always been tolled, first in both directions and from 1993 northbound only, with the toll plaza situated in the south bank of the Tagus river. At the time of the opening, one had to park the car and walk on foot to buy the toll ticket which cost 20 escudos. In June 14, 1994, the Government, which had run the bridge, 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. In 2006, the toll is set at 1.20 euro (for passenger cars).
Since June 30, 1999, the lower platform carries a two-track railroad. For that purpose, the bridge underwent extensive structural reinforcements, namely a second set of main cables, placed above the original set, for which the main towers had to be augmented in height. The train had been part of the initial project but had been dropped for cost reasons, and the initial structure had been lightened. Original builder American Bridge Company was called again for the job, performing the first ever aerial spinning for additional main cables on a loaded, fully operational suspension bridge.
The financial projections had the bridge fully paid in 20 years but traffic soon was way above anything predicted and has since been kept saturated despite the enlargement from four to six lanes, the addition of the train crossing, and even 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 now.
[edit] Numbers
In 2006, a daily average of 150,000 cars cross the bridge, including 7,000 on the peak hour. Train traffic is also intensive, 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.
[edit] See also
- Vasco da Gama Bridge - the other bridge serving Lisbon.
[edit] External links
