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Timber and glass are materials with aesthetically pleasing properties. If the materials can be combined appropriately, drawbacks can be overcome and the beneficial mechanical properties utilised and timber/glass elements can be a natural part of the load-carrying structure of buildings. Since glass is a brittle material, an important task for the timber is to provide redundancy – a glass failure should not lead to a catastrophic failure of the entire structural element. This paper presents results from ongoing research related to load-bearing components made of timber and glass. Results from tests on small timber/glass bond-line specimens, recently submitted for publication, are briefly presented. The core of the paper is, however, a study of fourpoint bending tests on twelve timber/glass I-beams with acrylate adhesive. These I-beams had a nominal height of 240 mm and were designed with a web of 10 mm float glass and flanges of LVL (laminated veneer lumber), bonded together with an acrylate adhesive. The mean values of the beams imply that the ultimate load capacity is 240 % of the load when the fi rst crack in the glass appeared. Thus, the timber well fulfils the redundancy task of avoiding a catastrophic failure of the structural element.

Both timber and glass are materials that have aesthetically pleasing properties. An appealing idea is to combine them to overcome the drawbacks and utilise the beneficial mechanical properties. Adhesive bonding with an appropriate adhesive could provide a uniform stress distribution at the transition between the materials. This report presents a study of three different adhesives, silicone, acrylate and polyurethane. Intentionally, adhesives with a wide range of properties were chosen. The adhesive bonds between timber and glass were tested both in tension and in shear with rather small bonds, 800 mm2. Special fixtures were designed both for gluing and testing of the adhesive bond specimens studied. The results presented include a traditional study of strength, failure type and relative displacement measured with LVDT’s, but also an extended study with a non-contact optical 3D-deformation measuring system and finite element modelling. Of the adhesives tested, the acrylate (SikaFast 5215) performed best, both in tension and shear. The mean strength obtained for this adhesive was 3.0 MPa in tension and 4.5 MPa in shear. Even if an important factor when gluing glass is the load distribution ability, the flexible silicone adhesive has too low stiffness and strength for use in structural components, where structural refers to the ability of a component to carry loads other than its own weight., Glas och trä i samverkan - innovativa byggprodukter med mervärde

A wooden I-stud as a member of a light-frame timber wall is modelled with reducing flange width to simulate fire exposure. The stud is loaded with a vertical load and the effect of restraints from one gypsum board and the top and bottom rail is considered. Geometry and material values are chosen to correspond to a stud with flanges of solid wood and web of OSB (oriented strand board). A model with shell and beam elements is implemented in Abaqus. A buckling analysis is performed on a perfectly straight stud and then a geometrically nonlinear analysis is performed on a stud with an initial curvature. Both the buckling analysis and the geometrically nonlinear analysis show that even a large reduction of the flange width results only in moderate changes of the load-carrying capacity of the structure. In the report diagrams are presented from the geometrically nonlinear analysis where the critical load is easy to read once a failure stress is determined, but an estimate of the the failure stress is not given here.