Development of a safety concept for structures exposed to debris flow based on Grey numbers

Structures built have to be safe. This requirement is fulfilled by consideration of a safety concept for structures. Over time many such safety concepts have been developed. The present safety concepts are based on stochastic considerations (semi-probabilistic and probabilistic safety concept). The current development suggests, that all types of structures independent from there goal should follow the rules of such a probabilistic safety concepts. Additionally further safety concepts are developed parallel, which not only include some material inherent uncertainties, but also other uncertainties difficult to be included in stochastic investigations. Here only combined fuzzy-probabilistic safety concepts are mentioned. Especially for some natural processes, there is often not sufficient amount of data available to fulfil the requirements of stochastic techniques. In addition, the uncertainty reaches dimensions, which can not be dealt with standard stochastic procedures. In some regions techniques were modified to avoid the problem of insufficient data. For example in the Netherlands regional frequency analysis is used to extend the amount of data. But especially for natural hazards in Alpine regions this might not be appropriate and the high amount of uncertainty remains, for example for the estimation of debris flow volumes. Here newer mathematical techniques for the consideration of uncertainty might be applied. The author has used the Grey numbers techniques invented by Deng 1982 in China for flooding prediction. Since especially debris flow predictions is combined with high uncertainties, it might be appropriate to extend the safety concept for structures exposed to debris flow impacts considering Grey numbers. Therefore the goal of the research is the development of a combined Grey-model-stochastic safety concept for structures exposed to debris flow impacts considering high dimensions of uncertainty.