Ponte Maria Pia

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Coordinates: 41 ° 8 ′ 23 "  N , 8 ° 35 ′ 50"  W.

Ponte Maria Pia
Ponte Maria Pia
The Maria Pia Bridge, 2006
Crossing of Douro
place Porto / Vila Nova de Gaia
construction Truss - arch bridge
overall length 353 m
Longest span 160 m
height 61.20 m
start of building 1875
completion October 31, 1877
opening November 4, 1877
planner Gustave Eiffel / Théophile Seyrig
closure 1991
location
Ponte Maria Pia (Portugal)
Ponte Maria Pia
As Rendas da D. Maria (4315133043) .jpg
Partial view of the arch construction
p1

The Ponte Maria Pia , also Ponte D. Maria Pia (Eng. Maria Pia Bridge ) is a disused railway bridge over the Douro between Porto and Vila Nova de Gaia in Portugal .

It is the oldest of the still existing bridges over the Douro in Porto, but not the first. In front of it there was the Ponte das Barcas ship bridge , built in 1806 , which was replaced in 1842 by the Ponte pênsil , a suspension bridge that existed until the opening of the Ponte Dom Luís I in 1886. The function of the railway bridge was taken over in 1991 by the Ponte de São João .

The Ponte Maria Pia was the largest arch bridge in the world when it opened in 1877. Along with the Garabit Viaduct, it is Gustave Eiffel's most famous bridge .

description

The Ponte Maria Pia led the Linha do Norte with the Portuguese broad gauge (1665 mm) over the Douro. The bridge and with it the short distance between the train stations Vila Nova de Gaia and Porto-Campanhã naturally remained single-track when the Linha do Norte was expanded to double-track from the turn of the century.

It is 352.875 m long and is framed by two small tunnels. It can therefore cross the Douro at a height of 61.20 m, while the neighboring Ponte de São João needs a height of 66 m without a tunnel.

The wrought-iron , riveted truss bridge has a two-hinged arch with a span of 160 m. The crescent-shaped arch is 10 m high at the apex and is supported on the banks on two bearings , which are 15 m apart. The approximately 3 m wide girder is supported by two pillars on the arched foundations, one on each arch hips and one or two pillars on the bank slopes. In the middle of the arch, the road girder merges with the truss construction of the arch. On closer inspection, the arch is not round, but, like all truss arch bridges, consists of individual straight beams. The bridge originally weighed 1,450 tons.

history

The reason for the construction of the bridge

In the middle of the 19th century, Portugal also began building railways. In 1856 the first line from Lisbon to Carregado was opened. The Companhia Real dos Caminhos de Ferro Portugueses ( Royal Portuguese Railway Company ) continued the route to Santarém in 1862 and soon afterwards to Entroncamento . At the same time, the Linha do Norte began to be built from Vila Nova de Gaia to the south. The Vila Nova de Gaia station was opened as the terminus of the line that was continuously passable in 1864. However, the crossing of the Douro to the opposite Porto was still missing. The best route had been discussed and argued since 1852. Initial bridge designs were unsatisfactory, especially because they could not avoid steep inclines when crossing the Douro gorge.

construction of the bridge

The Companhia Real dos Caminhos de Ferro Portugueses , a company with a strong French equity stake, had received five offers and preliminary drafts for bridging the Douro Valley from its Comité de Paris, ie from the Paris-based committee of the board of directors, in 1872 and 1873, namely from Eiffel & Cie. , Fives-Lille , Le Creusot , Ernest Goüin et Cie. and Bergas et Cie. The government determined the final location of the bridge in 1875 and required an independent commission to review the five offers.

Eiffel's offer initially amounted to 965,000 francs. After some changes initiated by the commission, it was still significantly lower than the competitor's offers at CHF 1,200,000. Eiffel received the order, the final planning was worked out by his then partner Théophile Seyrig .

The official start of construction was on April 26, 1875. First, the implementation planning had to be worked out and checked, which took some time for the large construction project. On January 5, 1876, the foundation work could begin. In September 1876, the masonry work for the pillar bases, the iron pillars and the lateral sections of the deck girder were finished. In the following winter, floods hampered the planned progress of the work. Therefore, the assembly of the arch could only be started in March 1877.

The main part of the bridge, the large arch with a span of 160 meters, was cantilevered using a new method that had only recently been tested in the USA by J. Eads at the Eads Bridge in St. Louis, later named after him . This railway bridge over the Mississippi River had the widest span of 158.5 meters that existed at the time. A cantilevered assembly meant that arch elements were attached from both sides and held back with steel cables until the two segments met in the middle. A cable crane ran over the temporarily raised main pillars , with which the parts were lifted into their intended place.

The Maria Pia Bridge when it opened in 1877

Like all large buildings, the bridge is the work of several people. The engineer H. Dion was responsible for checking the calculation, Émile Nouguier and J. Compagnon were responsible for the coordination of the work and for the assembly.

The arch was closed on September 25, 1877. A high-level commission of Portuguese engineers carried out the acceptance test in October.

On October 31, 1877 the acceptance and all remaining work was completed. On November 4, 1877, the bridge was inaugurated by the Portuguese royal couple Luís I and his wife Maria Pia . The bridge still bears the name of this queen today. Well integrated into the great landscape, it has become a landmark of the city of Porto.

Decommissioning

The Maria Pia Bridge was used by the Portuguese railways until 1991. Since it is only a single track and recently allowed a top speed of only 20 km / h, the rail traffic was moved over the Douro to the newly built Ponte de São João . After a long period of neglect, maintenance work was carried out in 2009, but no new use is foreseeable.

Others

Gustave Eiffel built the Garabit Viaduct at Saint-Flour ( France ), twice as high, in a similar design from 1881 to 1884 .

The Ponte Maria Pia was declared a Monumento Nacional in 1982 and added to the List of Historic Civil Engineering Landmarks in 1990 by the American Society of Civil Engineers .

The bridge is very often confused with the two-story Ponte Dom Luís I in the center of the city , over whose upper floor the new metro line for city traffic now runs.

See also

Web links

Commons : Ponte de D. Maria Pia  - Collection of images, videos and audio files

Individual evidence

  1. ↑ a b Ponte D. Maria Pia on SIPA - Sistema de Informação para o Património Arquitectónico
  2. ^ A b Xavier Cordeiro: A ponte Maria Pia. In: Gazeta dos Caminhos de Ferro , Volume 49, No. 1196 of October 16, 1937, pp. 493–494 (PDF; 6.9 MB)
  3. ↑ a b c d Frederico Abragão: Ligação de Lisboa com o Porto por Caminho de Ferro. In: Gazeta dos Caminhos de Ferro , 65th volume, No. 1561 from January 1, 1953, pp. 393–400 (PDF; 31 MB)
  4. ↑ Angela Sofia Garcia Salgueiro: A Companhia Real dos Caminhos de Ferro Portugueses, 1859-1891. Diss., Lisbon 2008, pp. 22 and 31
  5. ^ Ponte Maria Pia Bridge on the ASCE website