Edge strength model for structural glass based on the mirror zone depth

A reliable assessment of the edge strength becomes an important issue when designing structural glass elements in buildings. However, in the literature the edge strength of glass, dependent on the edge quality, is not well documented. Therefore, in this study an edge strength model was established and validated for commonly used edge finishings, namely ground, arrissed and cut. After testing at a high stress rate, the fracture mirror zone depth and the flaw depth were measured. For every edge finishing a reliable ratio between the fracture mirror zone depth and the initial flaw depth was found. A strength model based on the measurement of the mirror zone depth was established and validated, as the measurement of the mirror zone is much easier than the measurement of the flaw depth. Also, the mirror zone depth is independent of the loading rate and can be useful for forensic engineering