Le Pont De Normandie or the Normandy Bridge is a cable-stayed road bridge that is built across the river Seine linking the industrial city of Le Havre to the tourist and rural city of Honfleur in Normandy, northern France.
Le Pont De Normandie is 2,143.21 m (7,032 ft) long and features a stretch 856 m (2,808 ft) long between the two piers. It is primarily a motorway toll bridge; however, there is a footpath and a cycle lane in both directions to allow pedestrians and cyclists to cross the bridge. It was constructed between 1988 to 1995 and was at that time - the longest bridge in the world!
Tise magnificent bridge also held the record for the longest distance between piers for any cable-stayed bridge at that time.
However, this record was lost in 1999 to the Tatara Bridge in Japan and its initial record for length was lost in 2004 to the Rio-Antirrio bridge.
Designing the Pont de Normandie
The Pont de Normandie is widely regarded as one of the most beautiful European bridges with its slim and elegant construction. The bridge was designed by Michel Virlogeux. The chief architects involved in the project were François Doyelle and Charles Lavigne. Construction was handled by Bouygues, Campenon Bernard, Dumez, Monberg & Thorsen (now a part of MT Hoejgaard).
Nearly 1600 people were employed in the design and build of the bridge including designers, engineers, and suppliers.
The total construction cost of the bridge was $465 million, which was financed by Natixis. The owner of this spectacular bridge is the Chambre de commerce et d’industrie du Havre.
The Structure of Pont de Normandie
The main reasons for building a cable stay bridge instead of a suspension bridge was for it's improved stability in high wind loads at a competitive cost.
The Normandy Bridge has 184 cable stays to support the weight of the deck. A deck that is 23.6m wide in total, and allows for four lanes of traffic and two pedestrian walkways. The two pylons holding the cables are 214 m in height and weigh an incredible 20,000t.
On completion, the bridge was tested with a weight of Lorries equal to 16000t to assess its load limit and strength.
Aesthetic Components of the Pont de Normandie
The Normandy Bridge crossing the river Seine is a sight to behold. The deck of the bridge has a blue streak along the entire side of it, which creates the fabulous illusion of the deck floating in the sky.
The night time view of the Normandy Bridge is just as spectacular with individual blue lights running along the underside of the deck on either side to give the illusion of water reflecting onto the bottom of the bridge. There are also blue lights shining up from the base of each side of each pylon so as to continue the water effect all the way along the bridge.
Construction of the Pont de Normandie
The Pont de Normandie is predominantly a steel bridge, which was considered a landmark design during its time. MT Hoejgaard handled all the steel work including the fabrication and erection of the steel bridge deck, and also the supply and installation of the cable stays.
The construction of the vast foundations were performed between 1990 and 1992 while the construction of access ramps was handled between August 1991 and August 1993. The pylon construction was completed in August 1993, and in the following year the assembly of the metal section of the bridge's main deck was completed.
Construction of the pre-stressed concrete deck section of the main bridge by cantilever construction was over by October 1993.
A portion of the deck cantilevering out from the pylons was built as a hollow box made of pre-stressed concrete; however, the rest of the deck was made of steel. Interestingly, the earth's curvature and the immense length of the bridge required that the distance between the pylons had to be 2 cm greater at the top than at the base.
The pylons are made from pre-stressed concrete and are identical except that the north pylon is built in the river channel while the south pylon is built on the bank of the river. Hence extra care had to be taken for creating a sturdy foundation. The foundation consisted of 13 circular cofferdams with a diameter of 8.92m, and 12 connection cofferdams. All the cofferdams were raised to 16 m above the riverbed. The cofferdams aid in creating a dry area for construction to take place.
The bridge is equipped with mageba modular joints type LR9 and LR10. The joints allow movement and rotation in all three axes. The modular joints were installed in 1995, and on-site inspections revealed that there were no significant signs of wear and tear even after 10 years of use.
The blue streak that added to the aesthetic appeal of the bridge actually serves another purpose as well. The aerodynamic performance is improved by a blue painted aluminum cornice along the edge of bridge which serves to unify the two sections.
The cables are split into eight groups consisting of 23 each thus making up a total of 184 cables. The range of the cables’ length is 95m at its shortest and 460m at its longest. Each cable is made up of a bundle of wires, and each wire is made up of seven strands of galvanized steel. The cables are covered in a polyethylene sheath and coated with a petroleum-based wax, which fills the spaces between the wires and the sheath of the cable.
Interesting Facts of the Pont de Normandie
Some interesting facts about the Pont de Normandie:
- The Pont de Normandie has helped ease traffic congestion on the existing suspension bridge (Pont de Tancarville) across The Seine.
- Each cable can be removed individually for maintenance, thus enabling easy maintenance without having to shut down the entire bridge.
- Pedestrians and cyclists can cross the bridge free of charge.
- On completion, Le Pont de Normandie beat the record held by the Skarnsundet Bridge (1740 ft), Norway set in 1991, and the Quingzhou Minjang Bridge (china) in 1996.
Sources and Further Reading