Effects of Storm Duration and Sequencing on Armour Layer Damages

The design of the armour layer of a breakwater still allows further optimization and presents significant levels of uncertainties for selected parameters. The available analytical formulations are based on a small number of experiments and normally physical model tests are necessary in order to verify such analytical results. In this paper we consider a real storm as a benchmark to evaluate the reliability of the classical test methodology versus an innovative methodology based on synthetic storm profiles. A breakwater with a two layer cubic block armour has been used for these tests. The real storm has been scaled from a measured storm and the peak values of Hs, Tp have been used as the ‘design parameters’ for the classical methodology. The synthetic storm has been generated using the ‘Equivalent Magnitude Storm’ concept with a triangular shape. The relative damage, eroded area and depth have been used as the main evaluation parameters. The synthetic storm represents the damage evolution of the real storm well until the peak, but the damage does not increase after the peak, as in the real storm. The classical methodology by the end of the tests is returning too conservative results.