A new "incredible" key moment in the history of the reconstruction of Notre-Dame de Paris cathedral: engineers, architects and carpenters attended, Thursday in Briey (Meurthe-et-Moselle), a dress rehearsal for the assembly of the first floor of its famous spire.
Supported by a crane, operated delicately, in small jerks so as not to damage it, one of the parts of the shaft of the future spire of Notre-Dame de Paris will fit into the rest of the structure, mounted "blank" just a few tens of meters from the workshop where all the wooden parts of the complex frame are designed, in Lorraine.
"It's incredible, you realize", comments, in the front row, General Jean-Louis Georgelin, in charge of supervising the reconstruction of the cathedral. All eyes are on the piece, which fits perfectly into the already partly assembled structure.
This piece, raised in the air and placed with precision, alone weighs almost a ton. Each part of the barrel, taken in isolation, is fragile. But "once everything is assembled, it's very rigid", emphasizes Patrick Jouenne, spoiler (responsible for the site) for the reconstruction of the Notre-Dame spire.
The barrel, built in solid wood, comprises 285 parts, 350 assemblies, and will weigh, once fully assembled, 120 tons for 19 meters in height. Twenty-four pieces even intersect in a spectacular assembly, called the "X node". Every detail counts.
"Give the best"
Before the spectacular assembly phase of these elements making up the future spire, painstaking work was carried out, partly "invisible", with numerous studies.
The extremely complex plans were presented by the engineers, architects and other trades involved in this preliminary research, which must also take into account the shrinkage of the wood over time.
“All the nodes, all the geometries are different” and therefore require imagining hundreds of assembly plans, underlines Soline Pierrat-Bonneval, engineer at Etude carpente et structure bois, an engineering office. A thousand calculation points were also made to create "a digital twin" of the original arrow, according to a spokesperson.
More than 1.600 calculation combinations made it possible to anticipate all the events that could have an impact on the barrel, such as snow or wind.
Then, in this large warehouse entirely dedicated to the construction site in Briey, dozens of carpenters get down to work, plans under their eyes, in the precise work of the wood. An "honor", a "chance", and above all "a lot of pride", for Clément Leyris, one of them.
"We are perpetuating a tradition, we are participating in the restoration of one of the most beautiful French monuments. There is pressure, you have to give yourself, learn and give the best of yourself", confides to AFP Lucien Monchablon , another carpenter.
"We are almost halfway", in the reconstruction of the spire of Notre-Dame, wanted to be identical to that originally thought of in the XNUMXth century by Eugène Viollet-le-Duc, rejoiced in front of the press and local elected officials, one of the spokespersons for the site. The reconstruction of the spire began last March.
Once the barrel has been fully assembled "dry", in this test phase in Lorraine, it will be dismantled and transported by truck to Paris, where it will be reconstituted on the Notre-Dame site.
Once completed, the spire will weigh "about 370 tons" and will be 53 meters high, above the walls, Patrick Jouenne told AFP.
Last March, the stool, the lower part of the spire, was also mounted "white". He measures "5,50 m below the walls, so it's about 59 meters high", in total, he further noted.
For General Jean-Louis Georgelin, "at the end of the year, we will see the spire in the sky of Paris and we will see the trusses placed, both on the transepts, the nave and the choir, and finally we will find the silhouette of the cathedral".
The latter could reopen at the end of 2024. It will be a "success that surpasses all of us (...) It will be the success of France", underlined General Jean-Louis Georgelin.
The Editorial Board (with AFP)