Engineers design The Danish Cancer Centre together with Gehry Partners of Los Angeles
The Danish Cancer Centre was designed together with Gehry Partners of Los Angeles. The project is an extensive renovation of a 1918 building in Aarhus, Denmark inspired by the Maggie Centres in the U.K.
Gehry Partners concept preserved the facades of the existing building and inserted within this shell a highly unusual Mikado-like timber structure. The structure is held clear of the exterior walls, creating open canyons on either side to bring light to the lower levels. A completely glazed roof recreating the form of the building's original pitched roof completes the design.
An integral part of the design was the use of solid 18 by 18 Douglas Fir as the primary architectural expression and structural members. Of notable non-structural challenges include providing a pleasant internal environment under the glazed roof without mechanical cooling, using mostly natural ventilation through earthducts, and providing the building with discrete routing for the mechanical systems within its exposed structure. Also a mist-sprinkler system was implemented for the first time in Denmark on this project.
The internal structure consists of two floating floors above a basement level and 30 inclined timber columns. The floors are offset from each other creating a significant lean in the structure. To counteract this, the lower floor is held in place by three concrete storage cores. Thus the columns were fixed laterally at both their base and at their connection to the lower floor plate so cantilevering upwards and hold the upper floor in place.
Rather than using the old facades for stability 4 slender but stiff post-tensioned, high strength fibre-reinforced concrete columns have been placed in cavities at the four corners. The columns also carry the loads from the roof, which is transferred into the corner rafters by the stiff tubular ridge beam. The ridge beam collects the majority of the loads from the side rafters through bending stiff connections. This allows cross ties to be omitted.
An important consideration in the design was the twisting and cracking of the solid wooden members. Hence all members and details have been designed to all members to twist freely. Due to the large member sizes and the need to allow for large cracks to open and a very complex geometry a custom-made screw was also developed for the project. The design intent was to conceal all steel connections between the wooden floor beams. This was achieved by locating steel connectors on the top face of the beams in the shape of inverted double-T's.
Due to the complex geometry, Soren Jensen modelled the more than 500 unique connections in Revit and provided both steel and wood contractors with a total of more than 8000 fabrication drawings and cutting files for their machinery. Using prefabrication and assembly allowed for the on-site assembly of the structural members in just 4 weeks.