Adhesively bonded glass-metal façade elements with composite structural behaviour under in-plane and out-of-plane loading

Abstract

The structural efficiency of transparent façades can be increased by achieving a composite structural behaviour between the framing elements and the glass panes. The use of suitable intermediary materials is substantial for obtaining a composite structural behaviour for both out-of-plane and in-plane loading. This article presents two novel configurations for such glass-metal elements. For the first configuration, a perimetrical bonding with a silicone adhesive between the glass pane and the filigree metal framing is responsible for transferring stresses in out-of-plane direction, and grouting blocks are used near the glass pane corners for transferring stresses in in-plane direction. In the case of the second configuration, a perimetrical bonding with an acrylic adhesive between the glass pane and the filigree metal framing is responsible for transferring stresses in both out-of-plane and in-plane direction. Full-scale tests and finite element simulations with loads acting in three different directions, both separately and combined, are performed for the two configurations. The results of the tests performed under in-plane shear loading reveal a high load-bearing capacity of both configurations and show that failure is initiated within the adhesive joints. The numerical models, which include previously derived non-linear material models for the adhesives, allow a good prediction of the mechanical response of the investigated glass-metal elements. The presented load vs. displacement diagrams illustrate that the elements with acrylic adhesive behave stiffer both under out-of-plane and under in-plane loading before the adhesive starts to yield. Overall, the configuration with silicone adhesive and grouting represents a solution which can be applied in real projects based on existing technical approvals for the involved materials in similar applications. On the other hand, the configuration with acrylic adhesive indicates the potential of glass-metal elements with stiffer adhesives, assuming that the knowledge on such adhesives will continue to grow and that, eventually, new enhanced products will be developed by the adhesive industry.