Design of glass structures based on fracture mechanics and its integration in national and European design codes

Dr.-Ing. Geralt Siebert, University of the German Federal Armed Forces Munich, Chair for structural design and building physics

The use of glass in structural engineering opens a wide field for interesting applications. As it is a quite new subject only few regulations and design rules exist. At present these are [1], [2], [3] all basing on global safety concept and experience. They only cover a small field of application, for interesting structures special knowledge is needed and a special permit has to be applied for in Germany. In terms of this often design by testing is done where a copy of the real structure is built in laboratory and tested destructively. It is obvious that this is a process with high costs for time and money. Starting from recent research work at present a design code based on fracture mechanics and in line with the actual concept of partial safety factors is at development stage. To give an idea about this future principle and the background in this article the design based on fracture mechanics and concept of partial safety factors is presented.

Design of glass elements based on fracture mechanics is done in several steps.
- For a glass element with given geometry, loading (as function of time and magnitude) and material the stress is calculated.
- The resistance of the material is determined on basis of testing in laboratory.
- Using special factors of influence the above mentioned resistance (results of laboratory testing specimen) and stress (behaviour of real structural element) can be set to relation.
- By this a design equation based on maximal accepted failure probability or alternatively an estimated failure probability can be determined.

Of course already existing results can be used for single steps.

Finally short information is given about the actual application for standardisation in Germany (future code DIN 18008), in Austria (ÖORM 3716) and EN 13474.

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The Authors

Prof. Geralt Siebert Univ.-Prof. Dr.-Ing. Universität der Bundeswehr München Geralt Siebert, born in 1966, received his civil engineering degree from TU München. The doctor’s thesis about the application of architectural glass as load carrying structural element was accepted 1... Read more