Edge strength of cut and polished glass beams

For the past three decades, glass has become more frequently used for secondary construction elements in façade glazing, as well as for structural elements. In the latter case, the edge strength becomes an important issue when designing a structural glass beam or a façade fin. Different parameters affect the edge strength of glass, such as 1) the type of edge finishing and the supplier, 2) the size of the element and 3) the load duration. The first parameter affects the number and the shape of the edge flaws caused by cutting or polishing the edge. Secondly, the size effect is important because larger elements tend to have a greater probability of larger flaws. Finally, the load duration has an impact on the time-dependent strength. In this study, 16 series of glass specimens with different edge finishings and sizes were subjected to in-plane four-point bending tests at several loading rates. The environmental effect (i.e. humidity) was not examined, as all the tests were carried out under constant laboratory conditions. After comparing different distributions, the most appropriate distribution, i.e. Weibull, was used. The results of the series were compared statistically relative to the parameters mentioned above. The results indicate large variations in the edge strength, which are assumed to be related to the edge finishing and the glass supplier. A detailed manufacturing protocol is needed for a more accurate comparison of the results. Furthermore, unlike the size effect, the load duration effect was found to comply with earlier results given in literature.