Next generation structural silicone glazing

  • Charles D. Clift Curtain Wall Design and Consulting, Inc., TX
  • Lawrence D. Carbary Construction Industry Scientist, Dow Corning Corporation, Midland
  • Peter Hutley Curtain Wall Design and Consulting, Inc., TX
  • Jon Kimberlain Dow Corning Corporation, Elizabethtown


This paper presents an advanced engineering evaluation, using nonlinear analysis of hyper elastic material that provides significant improvement to structural silicone glazing (SSG) design in high performance curtain wall systems. Very high cladding wind pressures required in hurricane zones often result in bulky SSG profile dimensions. Architectural desire for aesthetically slender curtain wall framing sight-lines in combination with a desire to reduce aluminium usage led to optimization of silicone material geometry for better stress distribution.

To accomplish accurate simulation of predicted behaviour under structural load, robust stress-strain curves of the silicone material are essential. The silicone manufacturer provided physical property testing via a specialized laboratory protocol. A series of rigorous curve fit techniques were then made to closely model test data in the finite element computer analysis that accounts for nonlinear strain of hyper elastic silicone.

Comparison of this advanced design technique to traditional SSG design highlights differences in stress distribution contours in the silicone material. Simplified structural engineering per the traditional SSG design method does not provide accurate forecasting of material and stress optimization as shown in the advanced design.

Full-scale specimens subject to structural load testing were performed to verify the design capacity, not only for high wind pressure values, but also for debris impact per ASTM E1886 and ASTM E1996. Also, construction of the test specimens allowed development of SSG installation techniques necessitated by the unique geometry of the silicone profile. Finally, correlation of physical test results with theoretical simulations is made, so evaluation of design confidence is possible. This design technique will introduce significant engineering advancement to the curtain wall industry.

How to Cite
CLIFT, Charles D. et al. Next generation structural silicone glazing. Journal of Facade Design and Engineering, [S.l.], v. 2, n. 3-4, p. 137-162, june 2015. ISSN 2213-3038. Available at: <>. Date accessed: 12 dec. 2018. doi:


Structural silicone, high windloads, silicone fatigue testing, high design strength, finite element analysis, hurricane testing