Irregular Wave Action on Rubble-Mound Breakwaters

An investigation was undertaken to compare the effect of regular and irregular waves on a rubble-mound breakwater model. During the experiments water depth, breakwater, and wave characteristics were kept constant; wave heights were varied. Experiments were conducted to determine the damage in terms of the displaced number of stones. It was concluded that the damage on a rubble-mound break-water is related to the energy of the attacking wave. Experiments revealed that relating the damage to the total energy is inaccurate. Consequently, this concept was replaced by a relationship between the damage and the effective energy, which is the part of the energy including the energy of waves higher than the design wave. Therefore, it was shown experimentally that the effective energy determines the different the different effects of regular and irregular wave action on the breakwater. It was shown that regular waves have the same effect as the irregular waves when the significant wave heights equal the heights of regular waves.