From our special correspondent
This is a very symbolic step for the construction site of Notre-Dame de Paris. The spire of the cathedral, which culminates at almost 100 meters high, a virtuoso work by Eugène Viollet-le-Duc and Auguste Bellu, will begin to rise again in the sky of Paris, from next week. .
The structure, made up of around 2,000 pieces of oak with complex assemblies, 66 meters high, will be perched 30 meters high, placed on masonry dating from the 12th and 13th centuries. A challenge for architects and carpenters. “It is without doubt the most complex work in traditional carpentry in France, and the most technically ambitious”, points out Rémi Fromont, chief architect of historical monuments (ACMH), in charge of the wooden parts of the restoration site.
Thursday, March 16, in Briey (Meurthe-et-Moselle), near Metz, the final preparations took place before the start of operations on the Ile de la Cité. Carpenters, lifters, architects and a whole team from the public establishment responsible for the restoration of Notre-Dame were gathered for the “dry assembly” of the spire stool.
This base, in the form of a tripod, will rest on supports placed at the four corners of the crossing of the transept. “It is on the stool that all the descents of loads will be taken”, explains Patrick Jouenne, spoiler, traditional term designating the master carpenter journeyman in charge of drawing the blueprints and preparing the wood, who works for the group of Le Bras Frères (director), Asselin, Cruard Charpente and MdB Métiers du bois.
The trial assembly, a sort of general rehearsal, aims to test the fitting of the 110 pieces of the stool, comprising 150 very complex assemblies, and to anticipate any problems. “But everything is working well, we haven’t had any bad surprises,” rejoices Patrick Jouenne.
To reach this moment of satisfaction, a long preparatory work was necessary, carried out hand in hand between architects and carpenters. “We were able to refer to the plans left by Viollet-le-Duc and Bellu, which are extremely precise, explains Rémi Fromont. And for the few small uncertainties that we may have had, we went to see very similar works, such as the spiers of the Sainte-Chapelle in Paris and the Sainte-Croix cathedral in Orléans, made around the same time. , by the same carpenters, even if that of Notre-Dame is the most technically accomplished. These visits have been very useful to us”. “We worked with period documents and with photos, testifies for his part Patrick Jouenne. We had to draw everything, put everything into plans. »
Once the plans have been validated, the carpenters intervene by carrying out in the workshop the working drawings of the pieces drawn on the ground, according to the art of the layout registered in the intangible world heritage of Unesco. “It’s really the traditional know-how of carpenters, which consists in reproducing on the ground, on a scale of 1, a 3D structure in 2D, explains Aurélien Lamour de Caslou, manager of the Métiers du bois company. The pieces of wood are then placed on the lines to be cut with obligatory precision, otherwise nothing will fit together. »
Once “tested”, the arrow stool will be disassembled to be transported to Paris, at the foot of the cathedral. Its different parts will then be pre-assembled on the ground, before being raised above the transept crossing. “We know that Viollet-le-Duc had dismantled the vault of the crossing of the transept dating from the 18th century to mount the framework of its spire. We are going to proceed like him, since this vault disappeared in the fire, explains Rémi Fromont. Today, the diagonal arches of the crossing of the transept have been reassembled, and the oculus decorated with the four heads of angels has been restored. We will now be able to progress above the crossing, with the progressive assembly of the frame of the spire. »
The assembly of the frame will be accompanied by that of a gigantic scaffolding. Once at the top, Philippe Villeneuve, chief architect of historical monuments, will come and place the golden rooster. The spire frame is expected to be completed by the end of 2023. Roofing work can then begin, progressing from top to bottom. “The scaffolding will be removed as the cover progresses, gradually letting the arrow appear,” explains Sébastien Faure, director of operations.
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