Abstract of: A numerical and experimental approach to cold-bent timber-glass composite elements

Abstract

The current rise of wooden constructions, which is encouraged by a strong trend towards sustainability of our buildings, also engenders innovation in facade design and materials. Timber-glass composite elements are a novel interpretation of the  structural sealant glazing concept aiming at a reduction of the carbon footprint of facades by using materials from renewable resources. Already available facade systems based on the principle of timber-glass composite construction are applied in curtain walls, which is a rather conventional way. This paper assesses the feasibility of cold bended timberglass composite elements to widen the scope of possible applications to curved or freeform surfaces such as timber grid shells.  Cold bending appears an efficient way to adopt the flat element to a non-regularly shaped substructure. The twisting from an initial undeformed to a deflected state leads to permanent stresses in the glass as well as in the adhesive joint, the adapter and the screwed connection. Numerical models of a rectangular and a square-shaped timber-glass composite element help to understand the mechanical reactions in the individual components and the joint. The virtual components are deflected on one corner while the other three remain in plane. The cold bending of such elements is additionally assessed in life-size experiments. Shape and size correlate to those used in the numerical models to enable a validation of the virtual model. The derived stresses and time-depended deformations of the deflected test specimens yield a better understanding of the structural behavior and design of timber-glass composite elements.