Viaduc de Sylans
Coordinates: 46 ° 9 ′ 48 ″ N , 5 ° 39 ′ 49 ″ E
| Viaduc de Sylans | ||
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| place | above the Lac de Sylans | |
| construction | Prestressed concrete - truss bridge | |
| overall length | 1266 m | |
| Number of openings | 21st | |
| Longest span | 60 m | |
| start of building | 1986 | |
| completion | 1989 | |
| planner | Pierre Richard Bogumil Serafin |
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The Viaduc de Sylans is a section of the Autoroute A 40 about six kilometers east of Nantua in the Ain department of the Auvergne-Rhône-Alpes region in France .
The structure runs as a Lehnen viaduct ( slope bridge ) above the northern slope of Lac de Sylans .
The prestressed concrete structure was built by Bouygues between 1986 and 1989 . It deliberately served as a prototype for testing new construction methods.
Around 450 m to the west is the Viaduc des Glacières , which was also built by Bouygues and is essentially identical but only 214 m long .
description
The 1266 m long motorway bridge consists of two independent bridge structures, separate for each directional lane, which are staggered one above the other on the steep slope at a lateral distance of about 4.50 m.
Pierre Richard, the technical director of Bouygues, tried, among other things, to keep the weight of the superstructure as low as possible due to the difficult foundation conditions. Instead of a conventional hollow box with a trapezoidal cross-section and closed webs, Pierre Richard, in collaboration with the architect Bogumil Serafin, designed a system in which X-shaped crossed bars between the base and cover plate take on the role of webs. In the external view, this results in a sequence of St. Andrew's crosses up to the next pillar. In the cross-section, two series of crosses are also inserted between the outer base points on the base plate and a longitudinal beam in the middle of the cover plate, resulting in a W structure. Some of the tension cables are visible between these bars.
The pillars are in 4 m wide concrete boxes that are between 6 m and 35 m deep so that the pillars can be moved accordingly when moving on the slope. Some of the boxes are also secured by horizontal anchors in the mountain. The boxes are locked on the surface to prevent falling rocks and rock slides.
The superstructure has been made of precast segments prepared in the cantilever respectively lifted by a stem backbone at the two sides of a pillar and there with epoxy resin were bonded and clamped with clamping cables.
The construction method resulted in a weight saving in the superstructure of 15%, which meant longer spans, fewer pillars and cost savings in the foundation. On the other hand, there were difficulties in concreting the cross bars with their square cross-section of only 20 cm, which hardly left enough space for the concrete between the reinforcing bars . The problems generally associated with the execution of a prototype meant that the expected savings were neutralized on balance. Bouygues did not repeat this construction method.
Web links
- Viaduc de Sylans on Info-autoroute.com
Individual evidence
- ↑ a b c d Bernard Marrey: Les Ponts Modernes; 20 e siècle. Picard éditeur, Paris 1995, ISBN 2-7084-0484-9 , p. 207
- ↑ a b Viaduc de Sylans on Info-autoroute.com
- ^ Viaduc de Sylans contribution of the LCPC - Laboratoire Central des Ponts et Chaussées; archived on wikiwix