Buckling Strength of Glass Elements in Compression

Due to the high material compressive strength and typically slender cross sections, the design of structural elements made of glass (columns, beams, and shear panels) is limited by stability criteria. This paper describes several studies on the buckling strength of glass elements in compression. The main parameters having an influence on the load carrying behaviour of these elements – initial deformation, glass thickness and the visco-elastic behaviour of the PVB interlayer in laminated safety glass – will be described and characteristic values based on measurements on glass specimens will be given. Numerical and analytical models have been developed that are able to simulate column buckling tests which were carried out on single layered and laminated safety glass with PVB interlayer. The analytical model will be described in this paper. The models were used to further examine the influence of various parameters on the load carrying behaviour, whereof the main results will be presented. The study showed that the buckling strength of structural glass elements in compression is always limited by the tensile strength of the glass surface. Based on these results, design recommendations for single layered and laminated safety glass are proposed. A design concept with column buckling curves based on a slenderness ratio similar to the design of steel columns is not useful for glass as the slenderness ratio must be defined in terms of the tensile strength. The design of glass elements in compression might be carried out either by means of column buckling curves based on geometric slenderness or direct second order stress analysis.