In the Press: Spherical Objects!
Spheres have always been seen as a rather fantastical form for a building. Yet the sphere is in a geometric sense the most efficient form there is – and new technical innovations are making it easier to exploit this potential in practice.
Of all the radical and inventive geometric shapes that buildings can assume, a sphere is arguably the most fantastical. There is no cosmic law stating that buildings must be rectilinear, and curves are as much a feature of architecture as angles. But the sphere unsettles the preconceived visual, functional and structural notions about what buildings should be, by allowing the natural organic form to triumph over the rational, orthogonal geometries we commonly associate with architecture.
However, James O’Callaghan of specialist engineer Eckersley O’Callaghan believes glass offers key advantages over ETFE for spherical buildings. “ETFE needs to be in tension, which is generally created by making a double curvature – hence its cushion form. However, this means the surface of the sphere would not be smooth and lead to an inconsistent spherical geometry.
“Glass, however, can be formed over moulds to achieve a double curvature or bent via toughening furnaces to precisely achieve any desired geometry. It is also a hardwearing material that has longevity and performance that is not replicable in polymers like ETFE. It also has greater transparency and acoustically avoids the drumming effect when it rains, which can be overwhelming with large roof ETFE roof structures.”