The stress peak at the borehole of point-fitted IGU with undercut anchors

Abstract

The highest transparency in glass facades is obtained with point fitted glass units. Point fitted insulating glass units minimize thermal bridging and lead to glass facades with better energy efficiency. Though, insufficient knowledge is present to offer a design method for point fittings in insulating glass. Therefore research has been carried out to extend the existing SLG-design-method (Linear superposition of local and global stress components) of Beyer for point fitted single and laminated glass to insulation glass units. This paper presents the first results of this research campaign. Load bearing tests on point fittings in single glazing have been conducted. A finite element model of the point fitting is calibrated by strain comparison. A test campaign for the deviation of a material law for silicone, used as secondary sealant in the edge seal system, is presented. The verified FE-model is implemented in a selected insulation glass unit, and the influence of the edge distance of the point fitting, as well as the edge bond stiffness and geometry on the stress peak at the borehole is investigated. In addition, the size of the so called ‘local area’ is adjusted for insulation glass units.