In order to assess safety levels in glass structures, a scattered & inhomogeneous variety of mostly complicated resistance criteria is presently available, very often requiring specially developed softwares. For this reason, engineers who want to assess with reliability the actual safety level of glass structures of relevant economical importance are still obliged to undertake expensive experimental tests. In the attempt to overcome this problem, a new semi-probabilistic failure prediction method called "Design Crack Method" (DCM) was formulated. This is a compromise between the necessity to accurately model the complex mechanical behaviour of glass at breakage & the need to reduce the analytic complexity of the calculations. On the basis of Linear Elastic Fracture Mechanics, such aim has been reached in the present work. by defining a new quantity called Design Crack, characterized by a mathematical expression that depends on the probability of failure and on the surface damaging level. The proposed method, which is in accordance with the basic principles of the Structural Eurocodes, allows to predict glass lifetime taking into due account the influence of parameters like the surface extension and the loading time-history of the structural element. The results obtained in some applications with the D.C.M. method have been numerically compared in this paper with those of the existing most frequently used theoretical methods.
