Ingrandes Bridge
Coordinates: 47 ° 24 ′ 3 " N , 0 ° 55 ′ 8" W.
| Ingrandes Bridge | ||
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| use | Road bridge | |
| Crossing of | Loire | |
| place | Ingrandes-Le Fresne sur Loire | |
| construction | Suspension bridge | |
| overall length | 545 m | |
| Number of openings | eight | |
| Pillar spacing | 64.5 m | |
| Load capacity | 12 t | |
| start of building | 1867 | |
| completion | 1868 | |
| location | ||
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The Ingrandes Bridge is a historic suspension bridge that crosses the Loire with eight consecutive spans . It is still used as a road bridge and connects the village of Ingrandes-Le Fresne sur Loire on the north bank (the place was created in 2016 from the union of Ingrandes and the neighboring Le-Fresne-sur-Loire) with the one around 4 km south of the river situated Le Mesnil-en-Vallée in the French department of Maine-et-Loire .
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The two-lane bridge leads the départementale D6 route coming from north to Ingrandes over the Loire ; its continuation beyond the south bank is referred to as D150. Vehicle traffic on the bridge is limited to a total weight of 12 t, a vehicle height of 3 m and a maximum speed of 30 km / h. Pedestrians who want to venture the almost 600 m long route practically have to walk on the lane, as otherwise only the narrow upper side of the riveted side members is available to them after the originally existing footpaths have been removed in favor of the wider vehicles.
The nearest bridges (without any particular restrictions) are in Montjean-sur-Loire, 5 km upstream, and Saint-Florent-le-Vieil, 9 km downstream .
description
The Ingrandes bridge looks like various other multi-hip suspension bridges over the Loire, but surpasses it with its nine pylons and eight successive bridges - more than anywhere else. Like most of these suspension bridges, it only has suspension cables reaching from pylon tip to pylon tip, compensating cables (câbles d'équilibre) connecting the pylon tips and separate, multiple anchor cables. It is 545 m long including the anchor blocks sunk into the ground.
Its nine pylons made of stone masonry have center distances of 64.5 m each. The pylons are the same height with heights of approx. 7 m above the deck and approx. 7 m from there to the base. However, at 4 m, the middle pylon is significantly wider than the other pylons. The bases stand on a pile foundation made of 18 m long oak piles and are surrounded by a wide pile of stones to prevent scouring. For stiffening purposes, the pylon tips are connected by steel, accessible trusses, which were not originally available, but were only attached during the modernization in 1921.
Steel support plates are attached to the top of the pylons, to which the double support cables and the horizontally running, also double compensating cables are attached. The outermost pylon tips are anchored with 4-fold cables in the anchor blocks, which are largely sunk into the ground.
Vertical hangers attached to the suspension cables support the bridge deck. The modernization introduced by Ferdinand Arnodin in 1821 with three stay cables and 28 hangers in the middle area, which was not repeated during the reconstruction of the right half after the Second World War, is only preserved on the southern half of the bridge, which is on the left in the direction of the river .
The steel bridge deck rests on the cross girders attached to the hangers; the railing, designed as a half-timbered structure , is used for stiffening.
history
At the beginning of the 19th century there were only two bridges over the Loire between Tours and Nantes : in Saumur and in Les Ponts-de-Cé near Angers . The wire rope suspension bridges, which the Marc Seguin brothers introduced from the late 1820s and were soon offered in a similar form by their competitors, made it possible for the first time to bridge wide bodies of water at a fraction of the previous cost. From the 1830s a suspension bridge was decided in Ancenis and bridges in Chalonnes , Montjean , Ingrandes and Saint-Florent-le-Vieil were promised. However, the Ingrandes Bridge was delayed for decades due to differing interests and unsuccessful subscriptions to the toll- funded project.
Bridge from 1868
On June 9, 1867, the foundation stone was laid with a blessing by the local priest. The completed bridge was blessed on November 7, 1868 by the Bishop of Angers. It was essentially the same as today's bridge, except that its suspension cables were led over saddles on the pylon tops, which were not yet connected by steel walkways and the deck girders and the railings were still made of wood and they had no stay cables, but walkways on both sides.
Modernization from 1921–1922
After more than 50 years in use, the bridge was completely renovated in 1921 and 1922 by the Ferdinand Arnodin company . The pylon tops were connected by steel, accessible trusses to stiffen them. The side half-timbered railings were made of steel. The suspension cables and hangers were renewed. According to the Arnodin system, according to which all parts of a bridge should be interchangeable, separate supporting ropes and compensating ropes were each led from pylon tip to pylon tip and individually attached to the support plates there. Because of the increased loads, the bridge now had four-fold suspension cables on both sides, each with three stay cables and 28 hangers in the middle area of the bridge field.
War damage 1940–1944
The bridge was blown up by the French to stop the advance of German troops, then repaired, later bombed by Canadian and German planes and finally burned down by German troops.
Reconstruction in 1946
In 1946 the bridge was rebuilt by the Baudin Chateauneuf company: the piers were repaired or rebuilt, the bridge deck was replaced by a steel one and the four-fold suspension cables were replaced with stronger, double cables. The bridge was given its present shape.
Web links
Individual evidence
- ↑ According to the French spelling rules, the parts of compound place names are connected by hyphens. In the founding act of the new municipality, the prefectess of the Maine-et-Loire department stipulated that only the two former place names should be connected with a hyphen, but not the other parts of the name: Arrêté DRCL-BCL n ° 2015-116 du 31 December 2015 portant création de la commune nouvelle d'Ingrandes-Le Fresne sur Loire , Recueil des actes administratifs de la préfecture de Maine-et-Loire, n ° 100 of December 31, 2015 (PDF; 2.9 MB)
- ↑ The Dodhara Chandani Bridge in the southwest of Nepal, a modern pedestrian bridge, has twelve openings, but consists of four largely independent suspension bridges with two-sided anchoring fields and is therefore hardly comparable.
- ↑ a b c d e f Le Pont d'Ingrandes, par les élèves de l'école primaire publique (1984) ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. in the Supplément au Bulletin Communal - 1984 , an exceptionally detailed and comprehensive account of the bridge and its history prepared by the Ingrandes primary school.
- ↑ The 65 m usually mentioned in the sources add up to a center distance of the outermost pylons of 520 m, which is significantly larger than the distance of 516 m that can be read off in Google Earth.
- ↑ a b Les ponts de Chalonnes, Montjean, Saint-Florent et Ingrandes . In: J. Siraudeau (ed.): L'Anjou historique . Paraissant tous les deux mois à partir du mois de Juillet de chaque année. Onzième Année, N ° 1 - Juillet-Août 1910. J. Siraudeau, Angers 1910, p. 94 ( bnf.fr ).
- ^ Photo of the bridge from 1868
- ^ Photo of the bridge from 1868
- ↑ Photo of the bridge after the modernization from 1921–1922
