Featured Story – Louvre Abu Dhabi: A rain of light

A nebula of metal stars

Sunlight enters the dome through a ‘nebula of stars’ weighing over 7,500 tonnes – as much as the Eiffel Tower. The roof is composed of 7,850 star-shaped elements superimposed over eight layers. The stainless steel clad outer layers are separated from the aluminium inner layers by a five-meter high standalone steel structure. In total, the layers contain nearly 460,000 geometrically distinct intersections, linked by over 410,000 connection points. In addition to their differing shapes, the stars’ angular arrangement varies from one layer to the next, which complicates the passage of light.

The steel structure separating the layers is made of 85 monumental elements, or Super-Sized Elements (SSE). The SSE are subdivided into 11 unique modules, each weighing on average 50 tonnes. They are welded or fastened by bolted plates. The SSE are coated with paint that reflects the infrared energy of sunlight, contributing to lower temperatures inside the structure and also to enhanced colour vibrancy.

Stainless steel for durability and aesthetics

In addition to its complex geometry, the dome’s materials play a decisive role in the ‘rain of light’.

Extruded aluminium was used as the substructure of the eight layers of stars for its ease in terms of manufacturing, implementation, weight and corrosion resistance; and also for its light-reflecting capabilities.

The engineers and the architect used stainless steel for the four upper layers of the dome, which are the most exposed to the climate, but also the most visible. The 4,481 stars of the upper layers were all clad on their upper face with 0.8-mm thick sheets made of duplex stainless steel. These sheets were first welded to each other, then fastened to the aluminium substructure through neopreneinsulated joints to avoid any galvanic corrosion of the aluminium by the stainless steel. To completely separate the two metals, the underside of the stainless steel sheets are clad with an anti-corrosion protective polyethylene film. The cladding takes on the exact curvature of the surface of the stars; an angle of slightly less than 180°, allowing for the low height of the dome of 36 meters and its wide diameter of 180 meters, accentuating its lightweight effect.