Pont de Térénez
Coordinates: 48 ° 16 '8 " N , 4 ° 15' 49" W.
| Pont de Térénez | ||
|---|---|---|
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| use | Street | |
| Crossing of | Aulne | |
| place | Argol - Rosnoën | |
| Entertained by | Conseil Général du Finistère | |
| construction | Cable-stayed bridge | |
| overall length | 515 m | |
| Number of openings | 1 + 4 | |
| Longest span | 285 m | |
| start of building | 2007 | |
| opening | April 16, 2011 | |
| planner | Michel Virlogeux and Charles Lavigne | |
| location | ||
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Pont de Térénez is the name of three bridges over the mouth of the Aulne funnel in the Finistère department in Brittany . The new building is completed in 2011, the first curved in plan cable-stayed bridge in France, that is the first cable-stayed bridge in France, with a line extending in a curve road.
location
The Crozon peninsula in the south of the Bay of Brest is cut off from the northern parts of the Finistère department by the deeply cut funnel mouth of the Aulne, which extends far into the country. If you didn't want to take the ferry, the route from Crozon to Brest led for centuries over the bridges in Châteaulin over the Aulne and in Landerneau over the Élorn , a distance of around 100 km. The first Pont de Térénez, completed in 1925 on the Gc 21 road (today D 791 ) from Crozon to Le Faou, saved the detour via Châteaulin and shortened the route to 74 km. It crosses the Aulne between steep banks at a narrow point just before the confluence with the Bay of Brest. In 1930, the Pont de Plougastel over the Élorn saved the detour via Landerneau and shortened the route to 59 km.
First suspension bridge from 1925
In 1909 it was decided to build a suspension bridge , but the First World War interrupted the work, which could not be resumed until 1920. The bridge was 376 m long and had a span of 272 m. Their 62/68 m high pylons were made of masonry and were connected to one another by a wall made of masonry. The bridge plate was stabilized by lateral steel truss frames. The bridge had a clearance height of 38 m. The suspension bridge was opened on December 13, 1925. At that time it had the largest span of all European suspension bridges.
On August 24, 1944, the bridge was blown up by withdrawing German troops.
Second suspension bridge from 1952
After the war, a new suspension bridge was built in the same place with the same dimensions. However, slender reinforced concrete pylons were erected on the existing substructure of the pillars. As traffic increased with larger vehicles, the disadvantage of the bridge built between steep slopes across the river became apparent: at the ends of the bridge the road had to turn almost at a right angle. That slowed down traffic considerably. When meeting articulated lorries , one had to wait for the other to drive past. Damage to the concrete pylons as a result of an alkali-silica reaction was also found. The bridge has therefore been under close observation since 1992. It was canceled in 2014.
Cable-stayed bridge from 2011
From 1995 studies on a new bridge with improved traffic management were undertaken. The draft for a bridge about 60 m below the existing one, drawn up by the bridge construction engineer Michel Virlogeux , the architect Charles Lavigne and representatives of the state building planning, consulting and monitoring institution Sétra , was finally accepted for execution.
It is a cable-stayed bridge with a roadway running in a large curve, to which the access roads connect with equally wide arches. This alignment was made possible by the significantly higher position of the road slab compared to the old bridge, so that the access roads could be built above the steepest sections in flatter areas of the valley slopes. On the inside of the curve of the roadway, there is an outwardly inclined pylon on both banks, which is supported by an inclined pillar under the road surface, so that a large lambda results. 72 pairs of cables are attached to the pylons in a fan system, the lower ends of which are fixed on both sides of the curved carriageway, which technically represents an orderly system, but from the point of view of the viewer moving over the bridge there is constantly changing arrangements and diverse overlapping of the cables .
The bridge structure is a total of 515 m long. The large opening over the river has a span of 285 m, the two lateral fields have spans of 81.25 m and 33.70 m. The roadway with two lanes is 7.5 m wide; outside the rope fastenings, there are 2.40 m wide paths for pedestrians and cyclists. The lane curve in the middle part has a radius of 800 m, the more curved access roads have a radius of 200 m. The carriageway slab consists of prestressed concrete and was cantilevered with 7.50 m long concreting sections.
The pylons are almost 100 m high and are also made of prestressed concrete. Its cross-section initially tapers in order to widen again below the rope anchorages, which made special demands on the self-climbing formwork . At the top of the pylons there is a 119 t anchor block for the ropes, which was lifted in one piece by a mobile crane for assembly.
The builder of the bridge is the Conseil Général du Finistère . The construction work started in April 2007 and was carried out by VINCI Construction France in collaboration with some of its subsidiaries. The bridge was opened on April 16, 2011.
Web links
- Pont de Térénez (1925). In: Structurae
- Pont de Térénez (1951). In: Structurae
- Pont de Térénez (2011). In: Structurae
- Pont de Térénez on the website of the Conseil Général de Finistère (French)
- Website for the inauguration (PDF; 3.3 MB) with a detailed description and numerous photos
Individual evidence
- ↑ The Passerelle des deux Rives over the Rhine (Strasbourg / Kehl), opened in 2004, is a pedestrian bridge; the Sunniberg Bridge in Switzerland, which runs in a curve and a slope, was built in 1998.
- ↑ The Zähringer Bridge (Le Grand Pont Suspendu) in Friborg, opened in 1834, with a span of 273 m, had already been replaced by a viaduct at that time . The Wheeling Suspension Bridge over the Ohio in the USA, built in 1849, has a span of 308 m. The Firth of Forth Bridge in Scotland, completed in 1890, is a truss bridge and has a span of 521 m.
- ↑ Pont de Térénez. Derniers coups de pelle pour l'ancien pont. Article dated February 2, 2015 on ouest-france.fr
- ^ Sétra - Service d'études sur les transports, les routes et leurs aménagements
- ↑ Plans. VINCI Construction France, archived from the original on October 29, 2013 ; Retrieved November 26, 2014 (French).
- ↑ Partenaires. VINCI Construction France, archived from the original on October 29, 2013 ; accessed on November 26, 2014 (French, executing company).