GAČR No. 14-17950S „Composite action between glass panes connected by polymer interlayer“ 2014 – 2016

Goal of the project “Composite action between glass panes connected by polymer interlayers” is to determine and verify shear transfer coefficient, which defines the ratio of composite action of laminated glass under different conditions including material ageing. Laminated glass is nowadays frequently used also for load bearing glass elements whose design is based on the ultimate states, i.e. on the verification of the stress. From this point of view, it is important to know the real stress redistribution in laminated glass plates which are connected by transparent polymeric foils. Material properties of interlayers are time and temperature dependent. It means that under high temperature laminated glass is without any composite action because polymer materials are not able to transfer shear forces, shear modulus will be close to zero. On the contrary, temperature under 20°C leads to the hardening of material and to the higher values of shear modulus. Second crucial factor influenced shear modulus is load duration because creeping of polymer interlayer can be observed under long term load. Safety design of such kind of glass panes doesn’t take into the account composite action except wind load. It leads to the conservative but uneconomical design. Obtained results of solved project significantly contribute to better design of load bearing structural glass elements.

Representative stress-strain curves for PVB interlayer Trosifol BG R20
Representative stress-strain curves for PVB interlayer Trosifol ExtraStrong