Zur Unsicherheit der Abschätzung natürlicher Einwirkungen

The uncertainty of the estimation of natural life loads

This paper discusses a problem, which arose during some projects in the last years regarding the definition of characteristic and design loads for structures. As a result of several projects, which used sophisticated methods, we have to face the fact, that the uncertainty of the definition of the natural loadings is not decreasing, but increasing. This fact is heavily related to the extension of data series using historical data with their limited quality. Even further, the time validity of the estimated loadings suffers a shorter lifetime, since new results from research projects dealing with historical data coming up in an increasing frequency and may yield to significant changes of the loading values. This questions the design lifetime of structures in the region of 100 years and even further, the applicability of probabilistic as a method for the evaluation of the structural safety, if this method does not sustainably consider the permanently changing epistemic uncertainty.