Breakwaters and Closure Dams

Course Description

Design and construction of breakwaters and closure dams in estuaries and rivers. Functional requirements, determination of boundary conditions, spatial and constructional design and construction aspects of breakwaters and dams consisting of rock, sand and caissons. Overview and history of breakwater and closure dam construction. The general design principles of a breakwater and a closure dam. Determination of boundary conditions for dams and breakwaters, with special attention to the design frequency. Methods to determine the design wave height from wave statistics. Overview of other boundary conditions (geotechnical and hydraulic). Materials, quarries and rock properties. Various properties of the different types of dams and breakwaters, like stability of riprap in current and wave conditions, design of armour layer, natural rock and concrete elements. The use of caissons for breakwaters and closure dams. Computation of element size using classical formulae, partial safety coefficients and probabilistic methods. Plan and cross section of breakwaters. Practical examples of breakwaters and closure dams. Execution (marine or land based equipment) of the works. Failure mechanisms and (cost) optimisation. One-week exercise in which a group of two or three students has to design a breakwater and a closure dam.