Bent-on-Site Flat-Pack Delivery of a Timber Shell

Wisdome Stockholm is an extension to the Stockholm’s Technical Museum due to open in December 2023 featuring an innovative timber roof. The free-form gridshell overarches 24 by 47 meters, consists of five crossing layers of doubly curved beams and is completely prefabricated from laminated veneer lumber (LVL). Beam segments were bent and twisted on-site from 2,190 flat, CNC-cut LVL-lamellae and locked in shape by 3,500 wooden dowels to form a stiff structure. Several challenges arose during the 1.5 year of planning, most of them induced by early design decisions such as material choice: despite being less common than glued-laminated (glulam) beams for doubly curved timber gridshells, the use of LVLwas mandatory from the start. Furthermore, time and budget constraints did not allow for lamination and machining of doubly curved beams. The beams of the gridshell are composed of five layers of individually CNC-cut LVL-lamellae, thin enough to twist and bend. Only the lowest beam layer was pre-laminated to create a stiff base while the remaining lamellae were shipped to site flat-packed and bundled for assembly. The entire roofwas parametrically planned in 3D. Lamellaewere digitally unrolled, mapping all detailed connections from the twisted center surface to the flat lamella, and all were nested for 5-axis fabrication. The constructive system and digital process robustness was tested and validated using demonstrators as early as one month into the project, putting an early emphasis on fabrication and assembly. This paper discusses the workflow and problem-solving strategies implemented during the execution stage.