Freeform Wood – Calgary’s New Central Library
Calgarians are not joking when they put efforts to make their city a world class destination: the New Calgary Central Library, scheduled to open its doors to the public in 2018, is the centrepiece of Calgary’s East Village Redevelopment and a building worthy of all the attention it has already attracted. Architects from Snøhetta are joined by Dialog, Stuart Olson, Entuitive (the structural engineers), and StructureCraft to design and build this modern space “to inspire all”, as the City of Calgary envisions.
(Image courtesy Snøhetta)
Our scope, the wood soffit, makes up part of the “skin” of the building, an architectural feature of curved Western Red Cedar battens flowing along the ceiling and down to the walls, difficult to not catch the visitor’s attention. By default, such a feature soffit necessitates very careful attention to detail. Adding the extreme weather conditions the wood will have to endure, the fine, knife edge interface with the glass façade, and the fact that the soffit will be prefabricated into panels that will have to fit perfectly together on site, you have a considerable challenge.
A dimensionally complex project like this demands close coordination between the design and fabrication teams: having the workshop only steps away from our desks mitigates a large proportion of risk innate to such structures.
(Render view from the SW, showing the turning of the wood soffit into a wall. Image courtesy Snøhetta)
The final product for this project will be a unique geometry panel system with very low tolerances. The project is currently in the hands of our engineering & drawing office at StructureCraft, where the surface geometry is being parametrically modelled using geodesics to achieve the architectural intent while ensuring the curvature of the battens is kept at structurally acceptable limits.
(Bending cedar pieces to test their capacity and geometrical tolerance (pictured a 2m bending radius)
3D modeling of the entire structure is in progress, with its complex boundary conditions; we will be making drawings to assemble all the parts together, forming approximately 170 panels of curved Western Red Cedar with a robust back-structure to maintain its exact shape at the anticipated loads: geometrical (the curvature), environmental (wind and temperature extremes) as well as transport loads, since the panels will be constructed in our shop in Vancouver and transported to Calgary for erection.
The prefabrication of the panels will, in this case, reduce site time from several months to several weeks. Aside from the engineering complexities, the natural variability of Western Red Cedar in colour and grain texture is calling for some careful thinking on the aesthetics of the finished structure, while the gaps between the battens are being designed as small as possible while taking into account material, fabrication and construction tolerance limits. The battens will be divided into manageable lengths and put together end to end, following a staggered joint pattern incorporated in the parametric design.
(Looking from the south west corner, the mockup will be installed in the top-centre of the image. Image courtesy Stuart Olson / StructureCraftBuilders)
We will be publishing more details on our website project page as the project progresses.
