Abu Dhabi, UAESaturday 17 March 2018

Play of light entwined in design: The Louvre Abu Dhabi’s concrete cladding is far from simple

To achieve what Mr Faraut describes as an 'archaic effect' on the museum’s immaculately smooth walls, Louvre Abu Dhabi’s designers have had to employ a material that could not be more state-of-the-art.

Labourers repair minor imperfections to the ultra-high performance fibre reinforced concrete panels that form the cladding of the Louvre Abu Dhabi. Antoine Robertson / The National
Labourers repair minor imperfections to the ultra-high performance fibre reinforced concrete panels that form the cladding of the Louvre Abu Dhabi. Antoine Robertson / The National
Simplicity can be deceptive, as the white concrete cladding of the Louvre Abu Dhabi will reveal. The museum’s panels are as intricate in design as the canopy which will cover them, with both structures complementing one another.

When it comes to design, simple things are usually designed and made simply, and it is only when complex things cannot be simplified that they remain as they are.

But as anybody who has used touchscreen technology or even a particularly efficient website may have realised, achieving the semblance of simplicity can often be a very complex business indeed.

Such is the case with the cladding that now envelops the galleries that are nearing completion beneath the giant saucer-shaped roof of Louvre Abu Dhabi on Saadiyat Island.

At first sight, there could not be a greater contrast between the 180 metre-wide canopy and the “museum city” that shelters beneath it.

The complexity of the museum’s mighty canopy is visible for all to see. It is dense, multi-layered and interconnected, like a giant woven constellation or some enormous upturned nest.

The galleries that now sit beneath, however, could not appear more different. Dressed in what look like enormous blocks of smooth, finely-cut white stone, the buildings are the very model of simplicity; the stark contrast is intended, of course.

In one important respect, however, the museum’s buildings and canopy are more similar than they seem. Both rely on a complex system of cladding to achieve the effects desired by their architect, Ateliers Jean Nouvel (AJN).

In the case of the canopy, that cladding consists of 5,000 tonnes of supersized structural steel and 7,850 aluminium “stars”, while in the case of the buildings it involves 4,680 panels of a substance called ultra-high performance fibre reinforced concrete.

AJN has designed Louvre Abu Dhabi’s buildings to echo the architecture of a traditional Arabian community or souq, but it also hopes it will communicate a sense of serenity, strength and gravity of the kind that results from age-old processes and construction techniques.

“It needs to make sense overall. To create an illusion, you have to make every effort to create the sense that is intended,” says Damien Faraut, the site project leader with AJN from his team’s permanent office at the museum’s construction site.

“We want the appearance of dry, Cyclopean stone assembly,” the architect explains, referring to the kind of massive masonry that is more usually found in ancient Greek citadels such as Tiryns and Mycenae.

To achieve what Mr Faraut describes as an “archaic effect” on the museum’s immaculately smooth walls however, Louvre Abu Dhabi’s designers have had to employ a material that could not be more state-of-the-art.

Ultra-high performance fibre reinforced concrete is normally used on large-scale infrastructure projects such as tunnels and bridges. Unlike traditional reinforced concrete, which uses steel for its reinforcement, the museum’s specialist concrete relies on a matrix of glass fibres to increase its compressive and tensile strength.

It also benefits from minimal shrinkage and impermeability, an important quality for a material that will regularly come into contact with the seawater that will eventually flow between the museum’s precincts, turning the whole complex into a miniature Venice on the Arabian Gulf.

“The cladding is going to be very exposed,” Mr Faraut explains. “Some panels will be permanently submerged in seawater, so the material needs to be extremely strong and non-porous, and this material is the technical answer to that.”

Louvre Abu Dhabi’s concrete cladding is manufactured by Fibrex, an Abu Dhabi-based construction company that has used similar materials on the facades of the Sheikh Zayed Grand Mosque, the Emirates Palace hotel and the Foster + Partners-designed Abu Dhabi World Trade Centre and Central Market.

At Louvre Abu Dhabi, the result is a cladding system that operates like a giant three-dimensional jigsaw composed of more than 4,680 pieces, 3,821 of which are unique.

“Every one is unique because there is absolutely no repetition in the size or the height of the buildings,” says the architect, describing subtle differences in scale and composition that are intended to communicate an almost impalpable sense of a settlement that has been hand-crafted over time.

“The position of the doors or the openings and the proportions are always slightly different, so that is why all of the panels are different.”

As Stuart Keane, the senior owner’s representative with the museum’s developer, Abu Dhabi’s Tourism & Development Investment Company, explains, the bespoke nature of the cladding panels means they have much more in common with the museum’s dome above than appearances might suggest.

“Similar to the stars [in the canopy], each panel has its own unique location. Panel one, for example, cannot connect to panel five and each piece has to be installed in a certain sequence if all the cladding is to fit,” he says.

“This means that there’s a lot of coordination required to have the panels fabricated and ready for installation, and the construction sequence of the buildings dictates the fabrication process.

“Each building’s structural concrete has to be completed, the waterproofing has to be done, as does the insulation, before each panel can be installed.”

The largest panels, which are uniform in size, are being used to clad the museum’s “wearing wall”, which will be partially submerged once the Louvre Abu Dhabi site is flooded and seawater surrounds the museum. They measure up to 30 metres square and weigh in at almost 12 tonnes.

“Because they will be exposed to continuous wave action and because, theoretically, a boat might hit them, the panels on the wearing wall have stainless steel reinforcement on the inside,” says Mr Keane.

A subtle exercise in architectural composition, all of the panels have a chalky, stone-like appearance that flips between brilliant and off-white, flat matte and gloss depending upon the light, the weather conditions and the perspective of the viewer.

“It’s not a flat matte finish. It looks that way from certain angles, but when you look at it from an oblique angle you start to see some reflection,” says Mr Faraut.

“We were able to adjust the colour and the glossiness to a very precise level so the final selection was an extra-white semi-gloss.”

The ability to ensure a consistent finish was another reason why the material was selected for the museum’s cladding.

“From panel one to panel 3,000, it will always have the same colour,” explains Mr Keane.

“It’s also very easy to repair. In any construction, panels might get chipped as it is being installed but with this, if pieces are scratched or chipped, they can be sanded out and patched, and that blends right in, whereas if it was a regular concrete panel, you’d always see the patch.”

The finish of the museum’s external walls may seem like a minor detail, but as Mr Faraut explains, the way they respond to light is crucial to the success of a building whose design is predicated on the control and manipulation of what promises to be the museum’s piece de resistance, Jean Nouvel’s much-illustrated but little understood Rain of Light. Created by nothing more than the movement of the Sun and its passage through Louvre Abu Dhabi’s canopy, the Rain of Light will bathe the museum’s precincts in a constantly shifting display of kaleidoscopic, reflected light.

“Everybody knows the effect of light as it passes through [the canopy of] a tree. You can see that it creates round spots, not because of the shape of the openings [in the canopy] but because of the shape of the Sun itself,” says Mr Faraut.

“What is happening under the dome is similar, but it is also a little bit more than that. If you had just one layer with holes in it, you would see the shape of the opening being traced on the ground with some rounding around the edges because of the shape of the Sun. It’s not a triangle, for example, it’s a triangle with round edges because the Sun is round,” the architect explains.

“If you have one layer, the spot moves as the Sun moves, but if you have two layers, the combination between the openings in the two layers changes as the angle of the Sun changes.

“So, we have four layers [of cladding] above the dome and four layers below so the spots will not only move but appear and disappear because of the changing relationship between those openings and the angle of the Sun.”

The cladding of the museum’s precisely finished and pristine walls may be less starry than the cladding employed in its canopy, but both play a crucial role in the building’s sense of spectacle and drama, as Mr Faraut explains. “The surfaces of the building envelope are going to receive this light and the simplicity of their shapes. Their very flat and consistent character is the white page on which all of this can be accurately read. We will be able to read and contemplate this fantastic cinematography on these very simple white planes.”