Bestimmung der charakteristischen Betonfestigkeiten in Bestandstragwerken

Assessment of the Characteristic In-Situ Compressive Strength in Existing Structures. Shortcomings of DIN EN 13791

In order to verify the design resistance of existing structures, the structural engineer requires the characteristic material properties of the used building materials. The assessment of the characteristic in-situ compressive strength of structures is codified in DIN EN 13791:2008. However, as shown in this article, the application of DIN EN 13791 needs to be restricted to cases in which the conformity of an used strength class according to DIN EN 206-1 is in doubt. The characteristic in-situ compressive strength of existing structures should be assessed by common statistic methods. The recommended procedure for these cases is described in this article. Nevertheless, under adverse boundary conditions, the unreflecting application of statistic methods can lead to dubious results. Therefore, a competent engineer should verify these results.