ABSTRACT
The reliability rating system is developed making use not only of the traditional probabilistic techniques, borrowed from structural reliability, but also of subjective probabilities, implemented via the event trees method. The system is based on a new index, called Index of Inadequate Performance, which reflects the results of a simplified and approximated reliability analysis. A complete reliability analysis for a flood defence embankment would require the knowledge of the frequency of the load and the probability of failure for the range of possible loads in the form, for example, of a fragility curve. The rating system is conceived to provide the end user with a tool for a quick reliability assessment. In the reliability rating system the estimate of the probability of failure for piping through the embankment is based on the subjective probability approach. A reliability rating system for fluvial flood defence embankments is being developed at the University of Strathclyde, Glasgow.
