Maria Pia Bridge

41.139825 - 8.597147Koordinaten: 41 ° 8 ' 23.4 " N, 8 ° 35' 49.7 " W

F1

Railway

Rio Douro

The Maria Pia bridge ( Ponte Maria Pia Portuguese ) is a railway bridge over the Douro between Porto and Vila Nova de Gaia. It is next to the viaduct Garabit the most famous bridge of Gustave Eiffel.

He decided to build the bridge

On March 29, 1809, when the French invaded I. under the commander Napoleon stem from the north to Porto, tried to escape to the south over the River Douro citizens. Due to the excessive burden broke the former bridge, leaving thousands of citizens are to be drowned. Since then, there was no connection between the two places.

With the advent of rail transport increased the urgency of a new building bridge. As a rerouting of the railway would have meant a detour of twelve kilometers, it was decided, despite the difficult geographical conditions and the resulting expectation of significant technical problems for the bridge at this point.

Construction of the bridge

The Royal Railways of Portugal had in 1875 announced the bridging of the Douro Valley. The order was issued to the company Eiffel as the project with the design of Seyrig just under a third (1,200,000 francs ) should cost the most expensive competition design. Because of the large price difference, however, had doubts about the seriousness of Eiffel's offer. Therefore, it was the draft before the award of the contract examined by an independent Control Commission. The bridge was designed by Gustave Eiffel and Théophile Seyrig and built from 1875 to 1877.

The river was on the planned construction site 150 feet wide, the water depth was up to 20 meters. Steep banks and a very high flow rate of the Douro made ​​the construction of piers in the river bed impossible. To avoid the steep, sandy shore and the high flow rate of the Douro, the designers chose to build a large truss arch bridge with an average field of 160 m length. Pillars were fundamentalised in the embankment on both sides of the river to support.

Construction began in December 1875. Since the construction work should be completed in 21 months, had to be made quickly. To make up the building plans had therefore only two months. Eiffel himself, however, came in 1876 to the site.

The pillars, the masonry work and the straight roadway slabs were completed in September 1876. However handicapped flooding in winter 1876/77 the planned progress of the work. Therefore, the installation of the sheet could be taken only in March 1877 in attack. On 31 October 1877, finally managed to bridge the river.

The main piece of the bridge, the great arc of 160 meters should be cantilever mounted with a new procedure, which had only recently been tested in the USA by J. Eads at the later called after him Eads Bridge St. Louis. This railway bridge over the Mississippi River had the longest existing time span of 158.5 meters. A cantilevered mounting meant that were attached on both sides curved elements and retained with steel cables, until the two segments meet in the middle.

Like all great buildings, the bridge is a collaborative effort of several companies. The engineer H. Dion was responsible for the review of the calculation, Émile Nouguier and J. Compagnon were responsible for the coordination of the work and for assembly.

On 31 October 1877, the construction work was completed and inaugurated the bridge solemnly I. by the Portuguese royal couple Luís and his wife Maria Pia on 4 November 1877. Still bears the bridge the name of this queen. Good inserted into the magnificent landscape, it has become a landmark of the city of Porto.

Data

The Maria Pia bridge consists of a two-joint sheet of metal, carrying a metal road. The total length of the wrought-iron arch bridge is 352 m, the twin-track railway line on her superstructure extends 61.20 m above the waters of the Douro. The central arch was with a span of 160 m at the opening of 1877, the largest of its kind The weight of the bridge 1,450 t.

Decommissioning

The Maria Pia bridge is frequented until 1991 by the Portuguese railway. Since she is single track and / h has a maximum speed of 20 km, the railway traffic was routed over the Douro on the newly built São João Bridge. After long neglect of maintenance work was carried out in 2009, but no new usage is foreseeable.

Others

Gustave Eiffel built from 1881 to 1884 in a similar design to double the Garabit viaduct at Saint -Flour (France).

The Ponte Maria Pia was taken in 1990 by the American Society of Civil Engineers in the List of Historic Civil Engineering Landmarks.

The bridge is very often confused with the lying in the center of two storey Ponte Dom Luís I, on the upper floor today drives the new metro line of urban transport.