ABSTRACT
The main choice facing the designer of a breakwater is the choice between a structure of the rubble mound type and one of the monolithic type. The advantages and disadvantages of each are therefore repeated here. Some of these are site specific and some are valid for the present time only. The designer must therefore carefully assess in which direction he should move. Advantages of the rubble mounds are: ∑ Simple construction ∑ Withstands unequal settlements ∑ Large ratio between initial damage and collapse ∑ Many guidelines available for the designer
Disadvantages of the rubble mound are: ∑ Dependence on the availability of adequate quarry ∑ Large quantity of material required in deeper water ∑ Large space requirement ∑ Difficult to use as a quay wall
Advantages of the monolithic breakwater are: ∑ Short construction time on location ∑ Can function as quay wall ∑ Economical use of material in deeper water
Disadvantages of the monolithic breakwater are: ∑ Sensitivity to poor foundation conditions (settlements and liquefaction) ∑ Uncertainty about wave loads in breaking waves ∑ Complete and sudden failure when overloaded ∑ Reflection against vertical wall ∑ Limited support for the designer from guidelines and literature
In practice, this means that the choice of the basic type of breakwater will largely be made on the basis of wave-climate and soil conditions.
