AA/ETH-Pavilion

Lightweight structures are conventionally associated to membrane and pneumatic constructions. Aiming at rethinking this paradigm, a research collaboration between the EmTech Programme (AA School, London) and the DARCH Chair of Structural Design (ETH Zurich) has been recently activated to explore the potentials of the use of plywood in lightweight structural design. As a result of this collaboration, a temporary lightweight pavilion has been designed and built for the grand staircase of the ETH Science City Campus. The pavilion consists of three non-standard 18mm-thick panels of plywood (up to 11.0m by 2.5m) which have been individually bent around their transversal axis and connected together by a sequence of steel cables. Globally, this form-active structure has a maximum span of 8.5m and works as a system of self-stabilizing lightweight vaults. Moreover, the architectural qualities of its emerging spatial enclosure allows for the grand staircase to be activated as a new all-year meeting space for the students and faculty. A nonlinear static parametric digital model, based on the bending energy of the panels, has been calibrated with extensive physical tests and employed to explore different design solutions. The shape of the panels after the bending process emerged out of their initial non-deformed geometrical layout (geometrical parameter), the thickness and hierarchical organization of the wooden plies (material parameter) and the given load conditions (external constraint). By a systematic investigation into the defining parameters it has been possible to control the stiffness of the panels along their own longitudinal axis. This has allowed for their bending behaviour to be adjusted to achieve the required curvature. Employing panels of different lengths has made it possible to partially overlap adjacent elements and connect them together with a sequence of cables that stabilize the system and let the external forces to be evenly transferred within the structure.