CONCEPTUAL DESIGN OF RUBBLE MOUND BREAKWATERS

Abstract

This paper gives first an overall view of physical processes involved with rubble mound structures and a classification of these structures. After the description of governing parameters, the hydraulic response is treated. This is divided into: - Wave run-up and run-down, - Wave overtopping, - Wave transmission, - Wave reflection. The main part of the paper describes the structural response which is divided into: - Rock armour layers, - Armour layers with concrete units, - Low-crested structures, - Berm breakwaters, - Underlayers and filters, - Toe protection, - Breakwater head, - Longshore transport at berm breakwaters. The design tools given in this paper and by Delft Hydraulics' pc-program BREAKWAT are based on tests of schematised structures. Structures in prototype may differ (substantially) from the test-sections. Results, based on these design tools, can therefore only be used in a conceptual design. The confidence bands given for most formulae support the fact that reality may differ from the mean curve. It is advised to perform physical model investigations for detailed design of all important rubble mound structures.