Racking resistance of timber-glass wall elements using different types of adhesives

Abstract

In order to design energy-efficient timber-frame buildings with enlarged fixed glazing, mostly placed in the south-oriented external wall, it is of primary importance not only to take advantage of a high possible solar potential to heat the building, but also to assure a horizontal stability of such timber-glass structures. The paper presents the outcomes of a large experimental research on timber-glass wall elements where glass panes are directly bonded to the timber frame, which results in a load-bearing and visually interesting wall element suitable for lightweight timber structures. Three different types of adhesives (silicone, polyurethane and epoxy) were used with two different bonding line conditions to obtain an optimal type of connection which will be in praxis suitable for wall elements subjected to either monotonic or dynamic load impact. In the presented experimental research, strain measurements were supported by additional numerical FE analysis. Only such detailed studies and analyses could lead to the complete understanding of the specimen’s failure mechanism. The failure mechanism depends primarily on the type of adhesive and the type of bonded joints. These two parameters have a decisive impact on the element ductility and are important for further research. The analysis of the measured and calculated values confirmed the predictions that the stiffness and load-bearing capacity of timber-glass wall elements crucially depend on the interaction between the wooden frame and glass, which in turn is a function of the flexibility of the particular type of adhesive used.