Safety Aspects for Vertical Wall Breakwaters

In this appendix some safety aspects in relation to vertical wall breakwaters are discussed. Breakwater structures such as vertical wall breakwaters are used under quite different conditions. The expected lifetime can be from 5 years (interim structure) to 100 years (permanent structure) and the accepted level of probability of failure in the expected lifetime can vary from a very small number, e.g. 10-4 if failure of the breakwater results in significant damage to large probabilities, e.g. 0.5 if the consequences are insignificant. This has to be taken into account when discussing safety aspects and possible level I and D code formats. In the following first the most important failure modes are briefly described, see section 2. It is assumed that the failure modes can be modelled by limit state functions. Wave load models are described in section 3. In section 5 uncertainties related to the parameters used in the limit state functions and to the mathematical models are discussed and statistical models are suggested.