The Rolex Learning Center designed by the Japanese architectural practice SANAA, opened on 22 February 2010.
Located centrally on the EPFL campus, and its new hub, the building is essentially one continuous structure spread over a site of 88,000m2: The building is rectangular in plan, but appears to be more organic in shape because of the way that its roof and floor undulate gently, always in parallel. With few visible supports, the building touches the ground lightly, leaving an expanse of open space beneath which draws people from all sides towards a central entrance.
The topography lends an extraordinary fluidity to the building's flexible open plan – a flow that is emphasised by fourteen voids in the structure, of varying dimensions. These are glazed and create a series of softly rounded external 'patios', as the architects describe them. The patios are social spaces and provide a visual link between the inside and the outside.
The building is made up of two 'shells' inside wich are 11 under-stressed arches. The smaller shell sits on four arches, 30-40 metres long, while the larger shell rests on seven arches, 55-90 metres long. The arches are held by 70 underground pre-stressed cables.
The framework is composite; the main beams are IPE400 or 400mm high castellated sections, the purlins are laminated beams for the curved areas and IPE300 in flat areas. They are covered by trapezoidal structural steel roof deckings.
127mm diameter round steel tubes bear the cross girders except round the patios where they rest upon a ring made of square steel tubes supported by rectangular hollow sections.
The main challenge of the project for the metal manufacturer was the non-repetitive and complex geometry of the building which required a great number of different elements (almost 4,000 various design for frame elements and 1500 different assembling positions). For example, the 1800 seatings of the wood beams are positioned differently on the metal rails (900 different wood beams). The 14 patios have further complicated things with their three-dimensional curves, all different and unusual.
One problem at the assembly was the mounting of a shifting frame (temperature + flowing). The expected deformation of the floor on which the metal frame is assembled can reach 15cm in places.

Civil Works, including foundation and piles: Losinger Construction
Concrete for “shell” provided by: Holcim
Pre-stressed cables: Freyssinet
Roof steel beams, columns, braces: Sottas
Roof wood beams: Ducret-Orges

Rolex Learning Center website: www.rolexlearningcenter.ch