Structural Morphology of VACUUMATICS 3D Formwork Systems: Constructing Thin Concrete Shells with 'Nothing'

Vacuumatics consist of unbound particles inside a flexible membrane enclosure of which the internal air is removed to create a pressure difference with the ambient (atmospheric) pressure. This ‘externally’ acting ‘vacuum pressure’ stabilises the unbound particles into their present configuration. The ability to adjust the level of under-pressure, referred to as the ‘flexibility control’ of Vacuumatics, enables vacuumatics structures to be ‘freely’ shaped into almost any thinkable shape. From practical point of view the shaping of Vacuumatics is considered by deforming an initially flat structure. Furthermore, by locally changing the configuration of the unbound particles imprints can be made into the surface texture of the structure. Also, objects can be added in between the particle filling and the membrane envelope, which enables additional customisation of the structure. By effectively utilising this adaptability of shape as well as surface texture, Vacuumatics can be applied as a self-supporting formwork structure to produce ‘freely’ curved concrete structures with customised surface textures. The flexibility control of Vacuumatics is considered in this paper from a structural as well as morphological point of view, elaborating two shape design methods referred to as the ‘suspension method’ and the ‘lifting method’. A real-time concrete shell construction illustrates the effectiveness of using Vacuumatics as a flexible formwork technique.