Glued timber-concrete composite slabs made of beech glued laminated timber
Summary
Timber-concrete composite (TCC) slabs offer a combination of the advantages of both construction materials, both in terms of structural capacity and building physics. For this reason, they are nowadays widely used as one of the preferred slab systems for tall timber and timber-hybrid buildings, which are seen as the future of the sustainably built environment. A major criterion in the structural design of TCC slabs is the stiffness of the connection between timber and concrete. A stiff connection between the two materials enables a slender design of the slab system, whereas a softer connection comparatively results in larger cross-sections. The most slender and material-saving design is enabled by a glued connection. However, glued connections between timber and concrete are still non-existent in practice due to the lack of research and material development on such connections.
This project aims at tackling this issue by the development of novel application-friendly and performative adhesive systems for timber and concrete. Hereby, a key innovation is not only the development of glued connection systems, but also the usage of Swiss hardwood timber, more precisely, glued laminated timber made out of European beech square laminated rods (German: Buche Stabschichtholz). The usage of hardwood timber products as structural elements is motivated on the one hand by the recent and prospected changes in the tree species composition of European forests due to climate change. On the other hand, the higher strength classes of hardwood products also result in higher effective stiffness, enabling the design of even more slender TCC slabs as compared to the case when softwood timber products are used. The novel TCC systems in development will be subject to short-term and long-term structural testing in the form of building-scale test specimens in order to provide design guidelines and promote a fast application in practice.
Support
This project is carried out in collaboration with Empa Cellulose & Wood Materials, Sika Technology AG and Fagus Suisse SA and is kindly supported by Innosuisse, the Swiss Innovation Agency.