Cantilevered Laminated Glass Balustrades – Comparing Testing and Calculations

Glass has become a popular material for use in balustrades, guards, and railings. Historically, monolithic tempered glass has been primarily used, but with the recent changes to the International Building Code (IBC 2015), laminates with heat strengthened or tempered glass is now recommended. One growing application is cantilevered balustrades where the glass is only secured at the bottom in a base shoe leaving the other three sides without support. With laminated glass, cement based grouts have been known to lead to delaminations and breakage. As the use of laminated glass continues to increase in cantilevered balustrades applications, new materials for securing the glass in the base-shoe has been developed such as dry glaze systems and non-cement containing grouts. With these new installation techniques and materials, questions have arisen over how to properly define the support conditions when using finite element analysis software such as SJ Mepla. To answer these questions, testing was conducted on laminates made with standard PVB, stiff PVB, and ionoplast interlayers, and compared to FEM analysis and with the linear load formula found in ASTM E1300 appendix X9.

Vaughn Schauss

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