The edge strength of glass is affected by the load history. To quantify this effect, 12 series of glass specimens were subjected to either linearly increased (reference value), constant or cyclic loading. For constant loading the experimental values could be accurately predicted by linear elastic fracture mechanics (LEFM). However, for cyclic loading the LEFM prediction was 4-8% more conservative than the test results. Furthermore, a comparison of the experimental results with the prediction method provided in the standards shows that for cyclic loading the number of cycles should be taken into account in the rules of the standards.@en

Designing structural elements requires accurate glass edge strength values. However, these values are poorly documented in the existing standards. In several cases, the only possibility is to perform design assisted by testing according to EN 1990 annex D. In the existing testing standard EN 1288-1, the required number of specimens in order to estimate mean or characteristic values of glass strength is not specified. This standard only mentions that a low crack probability can require large numbers of specimens to estimate a characteristic strength value. In this project, 4 mm glass specimens with simple cut edges are subjected to in-plane four-point bending tests (100 test specimens) and the results from this large test program are used in order to estimate the influence of the number of test specimens on the estimates of glass strength values.@en