Lightweight Insulating Glass Unit from design to production
With the inscription “The Materials are Iron and Glass”, the medal from the 1851 World’s Exhibition also aptly describes the Crystal Palace and the botanical gardens of the University of Bern, which were built around 1860. The filigree steel structure, which is protected as a historic monument, must be preserved. In order to ensure the load-bearing safety of this structure with as few reinforcement measures as possible, the weight of the roof glazing is reduced to an absolute minimum. A variant study of possible insulating glass units is carried out within the framework of the building physics and monument preservation constraints, as well as considering the radiation that is important for plant growth. The further development of glass refinement and the resulting improvement in glass properties play a decisive role in this. Lightweight and highly efficient chemically strengthened 0.7 mm thin glass and 4 mm thick low-E coated thermally toughened glass are combined in an insulating glass unit. A test concept was developed to test the load-bearing safety and personal safety of lightweight insulating glass and chemically strengthened glass. The strength, the influence of surface damage, the fracture pattern as a result of various loads and the residual load-bearing capacity were analysed. The results obtained fulfill the assumption that the impressive deformation capacity of the glass results in a high level of safety without being a safety risk. The radiation transmission of the entire lightweight insulating glass unit was measured and fulfilled the required specifications. After design, manufacture tests had to be carried out to produce the glasses on the automatic production line in order to reduce manufacturing costs.
Circularity in Construction, scaling up glass reuse with silicone
The laminar glass bonding process using silicone, initially presented at GPD2023, has been successfully applied to renovate the façade of the Herostrasse building in Zurich, Switzerland. This innovative approach combines glass and silicone to create intelligent hybrid materials that support the circularity of building materials. By utilizing window or spandrel glass at the end of its lifespan in combination with silicone, the glass can be repurposed as cladding material for façades. This glass-silicone hybrid can be easily separated after use, allowing both materials to be recycled. This paper reviews the mechanical (impact) and safety (fire) performance of the composite glass-silicone-frame. Observations from the Herostrasse building implementation are discussed, and potential pathways for scaling up the method to larger projects are explored. The re-manufacturing process holds significant potential, as the large amount of flat glass replaced annually in window renovations could be reused effectively. The flexibility in formats and shapes opens a wide range of applications, and cutting to size is straightforward. Machine vision and optimization tools enable the reuse of these glass elements in both conventional façades and new geometric configurations and designs.
