A 12m-high, free-standing dome inside a double-curvature gridshell roof - all in timber - is designed to boost interest in science and technology in Stockholm. How did architect Elding Oscarson do it?
What Wisdome, National Museum of Science and Technology
Where Stockholm, Sweden
Wisdome is a Swedish national project to build five interactive visualisation dome theatres that promote interest in science among the public and specialists. The third, in Stockholm, is under now construction at the National Museum of Science and Technology.
Elding Oscarson won the invited competition to design it in 2019. The dome came with a fixed shape and size; 12m tall with a diameter of 22m. Elding Oscarson’s task was to design its outer shell, the fit-out and the space that would contain it. The congested museum also wanted to use the former car park site to create a circulation and meeting hub with café.
In terms of its design, the practice wanted to make the dome free-standing, enclosed by the building but free from it structurally to ensure future flexibility. The first experiment placed the dome in a box which resulted in a huge volume. However in the ultimate design the roof drapes over the dome, dropping down to single storey at the building’s perimeter. The dome is at one end, creating an asymmetric form externally which signals that there is something special within.
Sponsored by timber company Stora Enso, the brief also stipulated that the building must be constructed using its LVL and CLT products. The challenge was how to design this 48m by 25m double-curvature roof. The vaulted gridshell, a collaboration with structural engineer Florian Kosche, became something that would demonstrate the technical possibilities of timber, inspired by Frei Otto’s 1975 Multihalle Mannheim.
‘There are plenty of cars, machines and aeroplanes in the museum,’ explains architect Johan Oscarson, ‘but there is little about construction.’
Stora Enso’s systems are used for almost everything. The roof is supported by a perimeter of LVL columns at 6m intervals to maximise ground floor openings to the courtyard terrace. To prevent the building succumbing the roof’s weight, column centres are drilled through with steel tension bars.
On top of the columns sits a three-sided box beam that supports the free-form gridshell. The most complex aspect of the design, this comprises a structure of LVL beams built up across four intersecting layers in 1.5-1.8m sections.
Each beam is made using five layers of 30mm-thick LVL boards constructed in pre-shaped, 10-12m long segments sent to site in flatpacks. The boards and lathes are connected by huge dowels and bolts. Each layer is slightly staggered for rigidity, but there are no rods or reinforcements. The four layers of beams are cloaked in a solid layer of LVL that forms the outer shape of the roof and contains the insulation. The roof covering is again timber; hard pine shakes. Inside, the outer shell of the Wisdome is made using CLT blocks, as is the small block containing the café bar and WC, and the floor. Only the bar is stainless steel.
Unable to find an appropriate domestic contractor, Swiss firm Blumer Lehmann was brought on board with its own team of structural engineers and a firm specialising in 3D production. Foundations started early in 2022 and the structure is due to open this autumn.