Grandfey Viaduct

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New Grandfey Bridge

The Grandfey Viaduct on the railway line from Bern to Friborg is one of the largest bridges in Switzerland.

location

At the hamlet of Grandfey in Granges-Paccot , around three kilometers north of the Freiburg train station, the train crosses the wide Saane valley, cut deep into the Molasse rock , to Düdingen .

The viaduct crosses the language border between French -speaking Switzerland and German-speaking Switzerland (" Röstigraben ").

history

First viaduct

Grandfey Viaduct from 1862

In 1856 the Lausanne – Friborg – Berne railway company commissioned the engineer Leopold Blotnitzki to carry out studies for this most complex construction project in their route network. The design was developed by a four-person commission, consisting of Messrs. Durbach, Karl Etzel , François Jacqmin and Wilhelm Nördling , as the Stuttgart- born engineer who worked in France at the time was called. The recently built Crumlin Viaduct in South Wales and the Sitter Viaduct near St. Gallen were taken into account in this planning . The detailed design created Ferdinand Mathieu , the chief engineer of the French iron and later steel company Schneider & Cie. in Le Creusot , which had received the metal construction contract for the bridge. The earthwork and masonry work was carried out by the Swiss company Wirth, Studer & Co.

The double-track bridge, built from 1857 to 1862, was 343 m long and 82 m high and consisted of six lattice pillars standing on mighty stone plinths, which carried a strong lattice girder on which the superstructure of the rails came to rest. The spans of the five central openings were each 48.75 m, that of the side openings 43.30 m. Inside the lattice girder there was a passage for pedestrians and small carts. The Grandfey Viaduct thus opened up a new passage across the long and very impassable Saane gorge for light land traffic.

The masonry stone pedestals were up to 32 m high so that their heads were all on the same level. The flow dividers of piers IV and V standing in the river were protected against the current by a limestone cladding.

The pillars consisted of 3.93 m long cast iron pipes, which were arranged on 11 floors, 43.20 m high and connected and stiffened with lattice-shaped wrought iron frameworks .

The track girder consisted of four wrought iron lattice girders with a center distance of 2.09 m. The passerelle for pedestrians was built in between the two middle girders.

The Grandfey Viaduct is considered to be the first bridge where Ferdinand Mathieu , the chief engineer at Schneider & Cie., Used the propulsion system he had invented . The lattice girder beam pushed over the valley served as a crane for building the first and then the next pillar.

1300 tons of cast iron and 700 tons of wrought iron (welded iron) were used for the pillars, and 1250 tons of wrought iron for the beams.

The Grandfey Viaduct influenced the Viaduc de Busseau planned by Nördling shortly afterwards and served as a model for the 1886–1890 also by Schneider & Cie. Malleco Viaduct built in Chile .

Because of the heavier trains, the bridge was rebuilt in 1892 for single-track traffic with a track in the middle and the speed was limited to 40 km / h.

Second viaduct

Grandfey Viaduct from 1927
Pedestrian path below the rails

With the electrification of the rail network of the Swiss Federal Railways, the bridge had to be strengthened to be able to carry the heavier and faster moving locomotives and train compositions. The Grandfey Viaduct was given its new design from 1925 to 1927, based on a concept already implemented by the SBB bridge construction office for the Le Day viaduct. For this purpose, the SBB called on the pioneer of large concrete structures in Switzerland, Robert Maillart , as a consulting engineer. Between the six completely concreted iron half-timbered columns lie wide, melan-style concrete arches with the renewed pedestrian path running over the apex. The five central arches have clear widths of 42 m. On the mighty main arches rests a long row of slender arcades that support the bed of the railway system. With the double row of arches, the large building takes on a monumental, classical form.

Due to the construction of the Schiffenen dam, which was completed in 1964, the lower part is now in the water of the Schiffenensee .

Passage and sculpture by Richard Serra

The passage through the Grandfey Viaduct is one of the most beautiful points in the network of hiking trails and cycle paths in the canton of Friborg.

At this passage there is a modern sculpture by the American artist Richard Serra . The work of art represents an L-shaped steel beam and was created in 1987. In August 2007, the SBB had two handrails attached to the work of art for safety reasons , which were then removed.

literature

Web links

Commons : Grandfey Viaduct  - collection of images, videos and audio files

Individual evidence

  1. ↑ The technical information is based on the article by Bühler: La reconstruction du viaduc de Grandfey . In: Bulletin technique de la Suisse romande . Volume (year): 51 (1925) issue 25, pp. 301–307 ( digitized on E-Periodica - Swiss electronic academic library service, ETH-Bibliothek)
  2. ↑ Bernard Marrey: Les Ponts Modern; 18 e –19 e siècles. Picard éditeur, Paris 1990, ISBN 2-7084-0401-6 , p. 210
  3. ↑ Grandfey - Timpani - Before Building the Bridge ?, page 12 (PDF; 8.5 MB)

Coordinates: 46 ° 49 ′ 35 "  N , 7 ° 10 ′ 4"  E ; CH1903:  579 335  /  186175