La Grande Arche – Facade construction par excellence07. June 2019
Heat, frost, moisture and air pollution – the passage of time affects even the most impressive buildings. “High wind loads and rain have also caused visible traces of wear and dirt to the facade of the multi-storey office building La Grande Arche in Paris”, says Steven-Henrik Maier, Market Manager France for the fixings specialist fischer SystemTec. “This caused distortions, spalling and cracks to the facade made of white Carrara marble. As a result, the decision was ultimately made to renovate the facade in 2015, after the idea was initially floated in 2009”.
The French architecture firm Valode & Pistre was put in charge of the building’s renovation and came to a far-reaching decision: a robust granite stone would be installed instead of the previously used marble. The previous attachment also represented a thorn in the flesh to the architects: They wanted the facade panel to be installed with fischer’s concealed undercut anchors instead of the mandrel anchors that were visible in every joint. It was the start of a wonderful collaboration – and a European cooperation project par excellence.
La Grande Arche – the new arc of triumph
The “Grande Arche” has been one of the most popular vantage points of Paris since its completion in 1989. And for good reason, as the building lies at the end of the eight-kilometre visual axis that runs from the Louvre art museum across the Champs-Élysées and the Arc de Triomphe all the way to the multi-storey office building. The monumental structure was designed by Danish architect Johann Otto von Spreckelsen, who wanted the cube-shaped arch to be regarded as a “gateway to the world”. With a height of 110 metres, the 35-storey office building has enough room that it could fit the Notre Dame de Paris Cathedral beneath it – including its spire that collapsed during the major fire on 15th April 2019.
The “Gateway to the World” crumbles – and fischer steps in
Steven-Henrik Maier was halfway through a degree course when the enquiry came from France in 2015. “In essence, the architects in charge wanted a more robust stone of a similar colour as the white Carrara marble and a fixing solution that was equally inconspicuous and safe”, the 26-year-old construction engineer says, summarising the requirements. Finding the new stone was less of an issue: after just a short period, those responsible agreed on the “Bethel White” granite that is obtained from a quarry in Vermont (USA).
Major technical challenges
Meanwhile, the technical challenges were disproportionately higher, particularly in the overhead facade area. On the one hand, this was due to the immense wind loads on site. “And on the other hand, because France does not have a local approval nor a test standard or anything similar apart from the European ETA for fixings with undercut anchors”, Steven-Henrik Maier remembers. “Our Technical Director Jean-Marc Berg, who is now President of fischer France, and his colleague Gilles Dallon, therefore had to do a lot of persuading“. And provide verifiable proof.
Those responsible for the project in France were therefore invited to the fischer headquarters in Waldachtal, where tests were carried out in the testing laboratory using the “Bethel White” granite and the fischer Zykon-panel anchor FZP-II-SO. This proved to be a success – the higher load values in comparison to common anchor systems convinced the client. “This was subsequently inspected by an independent testing institute in France and we were given the required ATEX certification”, Maier says.
Full range of services from a single source
With the technical solution involving installing the granite facade plates with fischer’s undercut anchors the project was ready to be implemented. A fischer project team at times consisting of six people took over the coordination of all the international companies involved. “We arranged the timely delivery of the granite in the right quantity and strength with the supplier of the stone in the US for the west/south construction phase (carried out by EDM). In parallel, we were coordinating all the requirements with the drilling operator in Spain. This ranged from defining the drilling rig and drill to the drilling drawings and the permissible tolerances”, Market Manager Steven-Henrik Maier says, summarising just some of the tasks. “That is typical for fischer“, the 26-year-old says, “we take care of everything from the project’s start to finish and provide the clients and partners with all the required information”.
A system for installing rear-ventilated facades
The fischer Zykon panel anchor FZP-II is mounted from the reverse, it is obscured in the joints and ensures form-fit and expansion-free installation in the conical undercut drill hole. Compared to edge fixings (pin, plug pin and slot fixings) this technique achieves lower panel bending moments and higher load-bearing capacities.
In addition, individual panels of the facade can easily be replaced, if required. Because differences in colour can be particularly conspicuous when it comes to natural stone, the French architecture firm Valode & Pistre took advantage of this opportunity during the renovation of “La Grande Arche” and changed the panels around to their liking.