There are currently no systematic studies in structural glass construction that describe the complex load-bearing behavior of joints made with silicone adhesives in a differentiated manner. Due to the very low level of knowledge of the mechanical behavior which changes in dependence of these influences, high methodical safety factors (in Germany e.g. factor 6 for short-term loads) are applied when dimensioning silicone joints in structural glass construction. This currently results in an over-dimensioning with simultaneous limitation of the design possibilities, which in practice often leads to a decision against the use of a bonded joint from an economic point of view in connection with reservations and high requirements of the building authorities.
The aim of the project is therefore to investigate changes in the mechanical behaviour of silicone adhesives and the corresponding characteristic values required for the design of silicone adhesives as a function of the duration of loading (short-term, long-term and vibration loading) with a focus on vibration loading and production-related inhomogeneities in small parts samples. These investigations include complex CT measurements to identify and evaluate inhomogeneities in each tested sample. Based on this, the superposition and thus the valence of the influences on each other is investigated. In order to transfer the results from the laboratory tests to concrete applications in a practical way, bonded parapet elements, which are executed at a PA member, will be monitored in situ immediately after installation during the project duration. Furthermore, identical scaled parapet elements with defined loads and production-related inhomogeneities will be examined under laboratory conditions. At the end of the project, design and construction rules for silicone bonds are derived, which take into account the influences of load duration and inhomogeneities in the best case by means of reduction factors. In this way, an evaluation is to be made possible, how high the proportion of the examined influences is at the current safety level and how large thereby the potential for a possible reduction of the methodical safety factor is.
