An Adjustable Mould for the Casting of Glass Voussoirs for the Construction of Fully Transparent Shell Structures
Keywords:Cast Glass, Shell Structures, Structural Glass, Adjustable Mould, Voussoir, Tessellation, Dry-Assembly
Compared to flat sheets of float glass, cast glass components have a thicker geometry and thus a high buckling resistance. This buckling resistance in combination with the high compressive strength of glass make cast glass components suitable for the construction of fully transparent shell structures that are mainly subjected to compressive stresses. Shell structures often have the shape of surfaces with varying Gaussian curvature. When constructing such a shell structure out of cast glass components, components of varying geometries are needed. An adjustable mould was developed that can be used for the casting of glass components (i.e. voussoirs) of varying geometries. The possible voussoir geometries that can be cast in the adjustable mould are limited to voussoirs with planar, convex, polygonal intrados and extrados. These voussoirs can be used to construct fully transparent shell structures. The voussoirs are dry-assembled with a rubber interlayer in between. Tongue and groove shaped interfaces ensure an interlocking connection. By tessellating a shell structure, the shell structure is divided into a discrete number of voussoirs that can be cast in the adjustable mould. Several aspects have to be taken into account when optimizing the tessellation pattern including planarity, interior angle size, face size and alignment to the flow of forces. A design was made of a shell structure that covers the courtyard of the Armamentarium in Delft. This shell structure served as a case study used to demonstrate the tessellating process and the use of the mould developed during this research.