Probablistic Design of Water-Retaining Structures

Abstract

Holland has a rich tradition in the field of dikes. This knowledge, together with the history of dam disasters, shows that complete safety is unattainable. Realizing this, a method for assessing the probability of failure of a system of water-retaining structures has to be developed.

First, all possible failure mechanisms of the structures and all other possible causes (management error, human error, etc.) have to be determined.

Then, the relation between all possible failure mechanisms and the ultimate consequence of a flood or complete drawdown has to be analyzed. fault tree is a very helpful tool for solving this problem.

Third, the probability of failure of the various mechanisms has to be determined by means of probabilistic calculations, and the probability of occurrence of the other causes has to be estimated on the basis of historical data.

Now, the probabilities of the base events (failure mechanisms and other causes) may be combined in the fault tree to derive the probability of failure of the water retaining system. And in the end, one must ask if this probability is acceptable from a socioeconomic point of view.