This is a meticulous and decisive, which began Monday, June 8, at Notre-Dame de Paris. A little over a year after the fire, the dismantling of the scaffolding damaged by the flames, a veritable sword of Damocles of 200 tons, suspended above the cathedral, has finally begun. Part of Mikado giant was due to start in march, but had to be postponed due to the confinement.
"This is a world first : a scaffold of this size-there which burns and melts, it never happened," stresses Xavier Rodriguez, director-general of Jarnias, the company responsible for cutting this behemoth of steel. Reinforcement of the sprockets, the installation of protective nets, stormwater management – "real enemy for the cathedral" – or the installation of sheeting, replacement of stained glass windows : from the fire, his business has intervened repeatedly to secure the Notre Dame. But the dismantling of the scaffold was to him only " a yard in the yard ".
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Cutting piece-by-piece
Europe Scaffolding, the company was in the process of climbing the scaffolding around the arrow for its restoration at the time of the fire, is in charge to remove the parts that can be. But, if their work is still standing, a good part of the 40 000 tubes of steel has melted under the effect of flames, making it impossible to disassemble classic.
Since the fire, they have looked at all possible options to remove the structure. "The number one priority, recalls Xavier Rodriguez is to be able to do in ensuring the safety of the men, but also to avoid causing more damage on the cathedral. "A preparation phase that lasted almost a year and need a careful observation of the scaffold.
For the cordistes can access the heart of the old edifice, two new have been installed and the other to support two beams of 32 meters long on which they will be hung. © Pascal Tournaire - JARNIAS
The method adopted is to send cordistes in the heart of the work to be cut, the reciprocating saw. Two new scaffolds were mounted on both sides of the former to support two beams of 32 metres aluminium by which the cordistes can go down. Two teams of five people take turns each day, supervised by a échafaudeur perched on a platform to 75 meters above the ground.
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"In every post, there is a briefing where we analyze the scaffolding and what we cut out to see what we can cut," says Xavier Rodriguez. The cordistes attach the pieces to cut out, cut out, and then put them in a box, suspended to the crane of 80 metres – the highest in Europe – installed this winter. "When it is full, they put themselves in safety, and it is evacuated. "It also takes out the pieces of arrow calcined trapped between the steel tubes. "Thursday, for example, they pulled out a huge piece of the arrow ! "
Avoid a collapse
The main fear remains a collapse of the scaffolding, which has already been surrounded by three ceinturages reinforcement to avoid such drama. The sensors have been installed and someone is continuously on a screen to follow the movements of the scaffold ". As soon as an alarm sounds, " stop everything and look at what triggered it ".
Hanging from the beams that overlook the scaffold, the cordistes cut out carefully the steel tubes melted to evacuate. © Pascal Tournaire - JARNIAS
" The goal, recalls Xavier Rodriguez is to be finished at the end of the summer or early fall. "But the rate of removal is strongly dependent on the weather : wind, storms or thunderstorms, and all construction must stop. "For this first week, the time is not with us, so that, during the containment, when it was necessary to do this work, it was a perfect time..."
The construction was beautiful to be outside the norm, " the work for our cordistes remains the same ", stresses the director general of Jarnias. "But the stakes and the responsibilities are important : it is not every day that you work on the world heritage of the humanity ! "
