Experimental investigation of numerical design method for point-supported glass

Calculating stresses in structural glass components is essential for design, but is especially complex for customized components like point-supported glass (PSG) balustrades. Stress concentrations are introduced at the discontinuities of the plates precisely where boundary conditions elicit maximum field stresses. Further complicating design, most published stress data for glass components are based on annealed, edge-supported glass experiments - with limited applicability to fully tempered (FT), PSG applications. This article presents experimental and numerical results for a typical application of FT glass as a PSG structural balustrade. Strain data from six FT, monolithic glass balusters loaded to both service and ultimate conditions indicates 55.2-MPa stresses at service load and 155-MPa stresses at failure. Additionally, a design algorithm is developed, using beam theory with stress concentration factors to establish preliminary thickness for use in an optimized numerical analysis to calculate stresses. Comparison of numerical and experimental data leads to the conclusion that FT, PSG balustrades are most accurately idealized by solid linear elements and translation-fixed, rotation-permitted boundary conditions at the support node.