Freeform Transparency

Abstract

Glass, a transparent and durable material with significant structural potential, is extensively used for architectural and structural applications in buildings. Existing approaches mostly use float glass, which is confined by planar designs, resulting in two-dimensional facades. Several examples of curved glass applications exist which, due to the limitations of current fabrication techniques, result in repetitive panels. Emerging architectural trends demand more fluid, three-dimensional freeform shapes, which present glass shaping processes cannot provide without incurring excessive costs and material waste in the fabrication process.

Research in other materials shows that flexible moulds are able to produce complex geometrical results. More recently, knitted fabric formworks have proven to be very successful in creating concrete shells of high complexity and low material usage and waste.

This thesis aims to address the gap by investigating the viability of using knitted basalt moulds for glass slumping, a novel fabrication approach that might allow for the manufacture of customizable, freeform curved glass components. The research investigates the possibility of this technology to accomplish extreme geometries while remaining simple and cost-effective in mould manufacture. The methodology of this thesis consists of a thorough literature research, experimental testing and a design application. The literature study investigates and compares present glass curving technologies and also the moulds used for each method to visual, geometrical, structural, and sustainability criteria. Flexible mould applications in other materials are also researched and compared to the ones used for glass.
The second part of the thesis is an experimental exploration. Basalt yarn is chosen to create hand-woven and CNC-knitted moulds to test with glass slumping. The experimental phase involves testing several knitted basalt moulds and combinations with coatings to determine ideal material combinations in order to improve surface quality and geometric precision. After reflecting on the experiment results, experimental data is used to create a final prototype attempting to achieve geometrical control and repeatability to prove the potential of the proposed
fabrication technique.

Finally, the third part of the thesis is a design application. Casa da Musica in Porto is chosen as a case study to recreate its glass façade in a freeform shape. Connection details between the glass panels are designed for the proposed facade design and the proposed fabrication of each panel is showcased.