Title: High performance contact materials for load bearing glass structures
Author(s): Jan EBERT, Bernhard WELLER, Stefan REICH
Keywords: glass structure, membrane structure, contact material
Abstract
In a recently finished research project the Technische Universität Dresden was involved in the development of a long span glass roof with in-plane loaded glazing, labelled as transparent space grid structure. Especially the activation of the in-plane load transfer – a structurally membrane behaviour – of the all-glass roof was main objective of the research. After the realisation of a few prototypes and a finished project within the last years, the research focus changed to the load application of in-plane forces into the glass edge. The load transfer into the brittle material glass must consider certain parameters that are not comparable to other construction materials. Contact materials, either solid or resins serve for the direct contact and transfer heavy compression loads. These block materials must possess certain surface, in some cases contradictory properties, mainly high compressive strength, but equally soft material; direct glass contact must not hurt the glass edge surface. A powerful material for the load application into the glass edge is the necessary condition for the construction of membrane glass roofs. In the performed research relevant high performance contact materials are considered for glass structures. A broad range of plastics is investigated on their ability to transfer large compressive stresses into the glass edge. The visco-elastic material behaviour under compressive stress is described by testing data and spring-damper- elements. Long term testing of the plastics under compression deliver relevant information about the material behaviour in glass structures over the structural lifetime. Cyclic testing allows determining the percentage of elastic, the visco-elastic and the viscous strain.
