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CODA

Big O

The challenge was to build the lightest doubly curved shell from very simple and inexpensive elements and maintaining a low-tech profile. For a week and with the help of 8 students we proposed to make a toroidal thin shell of wood, for the annual Hungarian wood festival HelloWood. The strategy was to make a geodesic gridshell from flat stripes following two conjugated beams of geodesic curves over the torus.
The advantage of this type of shell is the integration of elastic forming process and assembling. 100 prefabricated identical parts were assembled by overlapping connecting pieces. The torsion, added to the bending due to the initial deformation of the plank, caused pre-stresses of opposite sign to the stresses to which it would be affected afterwards. These pre-stresses generate a beneficial stiffening effect, both in the isolated element during placement and later globally. When all the planks were self-locked, the geometric stiffness of double curvature and the pre-stresses of all the elements conferred a global high stiffening effect contrasted with the thinness of the resistant section. The extraordinary good atmosphere in the festival was crucial to the success of the construction. Material used: 1.5 m3 of planned pine planks in 1x10 cm section, 400 pinned connections with metallic bolts and timber dowels, 50 thin micro pilotis made of 0,5 steel rods and 4x4cm pine sections