Reshaping breakwater: Description of the profile evolution / Irregular wave induced forces on armor unit on berm breakwater

In order to develop a model able to describe how berm breakwaters reshape under the attack of waves, a large quantity of data from 2D and 3D tests was collected and arranged in a database. The data were first standardised, and since data come from models with very different size, all the lengths were scaled with the nominal diameter (Dn50) of berm stones. Since the information regarding the wave conditions in shallow water or in front of the breakwater was not always available the wave conditions were estimated in front of the breakwater by using formulae proposed by Goda (1985) and Stive, (1986). The profiles were schematised as suggested by Vellinga (1986) and van der Meer (1988) using six parameters; with the aid of PCA the original variables were transformed into uncorrelated components describing decreasing quotes of the total variance. Three of them account for 95% of the variance of our data-base. In this manner the dimensionality of the phenomenon was reduced from six to three. Each component describes part of the behaviour of the reshaping breakwater and for each of them a model was developed relating components to the environmental and structural parameters. The model respects approximately (relatively to the 1st PC) the composition principle and gives results for any condition. At the end the model was compared with the experimental profiles and with the output of BREAKWAT.Berm Breakwater