Computer aided optimum design of rubble-mound breakwater cross-sections

Abstract

The computation of the optimum rubble-mound breakwater crosssection is executed on a micro-computer. The RUMBA computer package consists of two main parts: the optimization process is executed by a Turbo Pascal programme, the second part consists of editing functions written in AutoLISP. AutoLISP is the programming language within AutoCAD. The quarry production, divided into a number of categories, and long-term distributions of deep water wave heights and water levels, form the basis of the computation. Concrete armor units have been excluded from the computation. Deep water wave heights are converted to wave heights at site. A set of alternative cross-sections is computed based on both functional performance criteria, and Van der Meer's stability formulae for statically stable structures. Construction costs and maintenance costs are determined of each alternative. The optimum is derived by minimizing the sum of the construction costs and maintenance costs. Moreover, the programme provides means to economize the use of the quarry. At this stage the computer programme is useful for feasibility studies of harbour protection or coastal protection in regions, where use can be made of a quarry in the neighbourhood of the project site and the use of concrete armor units is excluded in advance. Briefly a method is described to extend the computer programme to the use of concrete armor units.