Project commissioned by the UsBarcelona festival organizers to CODA team of LiTA research group at BarcelonaTech, made possible by an enthusiastic crew of students. Restrictions were a very limited budget, and very short time to assemble and disassemble.
The system is section-independent so the arch shape is used to shelter and to unload self-weight by form. It was furthermore decided to build a toroid by closing a curved circular deployment path. Closing a curved spring in itself solves the endpoints longitudinal reactions, whereas the contracting spring force creates a simple pulling force to the interior, normal to the circular trajectory easily materialized by free rotating flag-type ground fixings.
To simplify logistics and minimize the use of material the arch was redesigned to fit into one single plywood board, by being polygonized. Due to the asymmetrical surface shrinking nature of the torus shape, a half circular heptagonal arch was decided for performing an asymmetrical stiffness. An extra chamfer operation is performed into the planks to ease angle assembling process.
Assembled pairs of arches are coupled to a placed arch in the top joint. The arch is deployed till reaching the next support where it is fixed. Only a small amount of energy was necessary to progressively fold the structure (only 4 persons were necessary to fold the whole structure in less than 20 minutes).