The Swiss got wood. Continuing the line of thought of those such as Alvar Aalto and Charles Eames, the Emergent Technologies and Design program (EmTech) of the Architectural Association (AA), London and the Chair of Structural Design at the Swiss Federal Institute of Technology (ETH), Zurich, have set out from an internal EmTech competition and built a decently sized, sunshade construct built from 18 mm bent plywood. The form is derived from the structural behaviour of over-sized bent plywood sheets. Because of the weight of such sheets (11x 2.5 m) the material becomes something which reacts to its own weight and actually lends to stability. The grain of the sheets is predominantly laid longitudinally- when the sheets are bent, the grain goes under tension, creating a force which is cancels with the inverse force created by gravity (the weight). Without the weight, the pieces would snap back to straight.
Courtesy of EmTech (AA) & ETH
The bending force is directed through the bent forms by way of cut made in the sheets. These enable a larger enclosure and lightens the structure’s potential wind load. Not only are these cuts functional, there’s also a bit of play in the consideration- the cuts cast light and shadow across the steps which are sat upon in warmer months. Differing lengths of ply sheets built multiple layers of vaults in the form which interlock creating a self-stabilized structure. Oh well, there are secondary stabilizing cables which distribute the load evenly over the vaults preventing any unplanned deformation.
As above the idea was launched from the winning entry of an internal EmTech competition. All above considerations were worked out by students at EmTech in conjuncture with a materials test and design studies workshop of EmTech students based at the ETH. They took inspiration from the multitude of works exemplary of the processes of working bent surfaces, performed in areas ranging from jewelry design to aircraft, crafted paper and boat design.
Courtesy of EmTech (AA) & ETH
Courtesy of EmTech (AA) & ETH
