Silicone bonded steel-glass joints under high temperature

The use of structural adhesive for the bonding of steel-to-glass elements increased along with the structural and aesthetic requirements of high-performance transparent building skins, providing better performance of the steel-glass assembly reducing the stress concentration in the glass ply. However, the behavior of bonded joints subjected to high temperatures and the alteration of their mechanical characteristics after a heating process are fields that need to be deepened. The present paper aims at providing an innovative contribution to the gap in the knowledge of the behavior of bonded joints at ambient temperatures up to 300 °C. A detailed overview of the test set-up followed by the results of the mechanical tests will be provided. The tests are composed of two main steps that are namely the heating at different temperatures of the joint specimens and the definition of the residual capacity of the joint, under tear or shear load. A comparison of the mechanical behavior will be provided for different structural adhesives: commonly used adhesive DC993, SG20, SG500, and SIKA265 characterized by a soft elastic modulus, and TSSA, a high strength structural glazing silicone film adhesive. The test allows proposing residual resistance criteria that, even if they are obtained for a specific type of steel-glass joint, provide useful information about the choice of the adhesive in cases in which high temperatures are expected. Finally, a finite model is calibrated on the basis of the experimental results, supplying information about the possible modeling choices and the influence of the specific geometry adopted in tests on the results