Glass Strength Under Point Loading
Parametric Determination of Probability of Breakage for Typical Panel Dimensions
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Overview
Abstract
Structural glass is used in a range of building applications, and while the ASTM E1300 has recently been updated to provide a design method to account for probabilistic failure models for a range of geometries under uniform loads, there does not exist detailed design information for point loads. While, ASTM E2751 provides an allowable stress based on a theoretical probability of breakage (POB) of 8/1000 from the appendix of ASTM E1300, these allowable stresses have only a loose correlation to POB and are not accurate for all glass configurations. To address this, the authors explore the effect of point loads on glass strength using the glass failure prediction model (GFPM) from E1300 to determines the allowable stress (or allowable load) for common glass lite geometry based on a POB of 8/1000 and 1/1000. Results allow practitioners to benchmark designs for monolithic and PVB laminated glass based on various point-support boundary conditions.
The parametric study investigates the maximum principle stresses and stress concentrations of specimen types subjected to out-of-plane bending due to a point load over 26 cm2(4 in2).The maximum point load is found for various 4-side supported glass lites at a POB of 8/1000 and 1/1000.
Authors
Joshua Schultz, Ph.D, P.E., LEED AP, ENV SP
Assistant Professor
Gonzaga University
schultzj@gonzaga.edu
John Knowles, PE SE
Vice President
Stutzki Engineering
john.knowles@stutzkiengineering.com
Kedar Malusare
Stutzki Engineering
kedar.malusare@stutzkiengineering.com
Keywords
Introduction
Structural glass applications, particularly façade and canopy elements, continue to grow in ubiquity as transparency and daylighting remain significant motivators of architectural design. However, current design procedures (i.e., elasticity and
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Method
A series of parametric finite element models were run using Abaqus FEA software (Abaqus, 2017) to obtain the maximum principle stresses and stress distributions. The modeling approach followed the methods
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Data
Maximum, deflections, U, principle stresses, S1, and stress distributions were found for the rectangular panels of varying aspect ratios (Figs 4-6). The stress distributions and deflected shapes of the panels
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Explanation
The design loads and related stresses presented in Figs 7-10, provide designers a simple reference for selection of geometries to meet desired POB for annealed and HS lites of 5.5
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Conclusion and Future Work
The results presented are for four side supported, 6 mm thick, annealed and HS glass types. Ongoing studies are being completed to build out a series of design tables for
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Acknowledgements
The authors gratefully acknowledge Stutzki Engineering for the use of images.
Rights and Permissions
ABAQUS: Multi-Purpose Finite Element Analysis Software, Dassault Systems. 2017
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