Wave Forces on a Composite Breakwater with Circular Cylinder Caissons

Abstract

There is limited information on wave forces on caisson breakwaters with circular caissons. In this paper we report from model tests on wave forces from regular waves on a composite breakwater with circular caissons in 55 m water depth. The results are compared with the Goda formula for wave forces on plain vertical wall caissons. The measured forces are approximately 20% lower than the results of the Goda formula for the ultimate limit state high waves (H = 16 m) and 25% for the accident limit state (H = 19.8 m). However, there have been some discussions on the accuracy of the Goda formula, from no over-prediction to approximately 10% over-prediction. Taking an over-prediction of 10% into account our results still indicate a 10%–15% force reduction for high waves by using vertical circular caissons instead of plain wall vertical caissons.