This document reviews the scour protection systems required around port structureswhere these are to be used for the berthing of vessels powered by water jet systems.The development of a scour protection system at Poole Harbour in Dorset has beendocumented and reviewed and a series of laboratory investigations were thenundertaken. This has enabled a greater understanding of the scour mechanisms fromthe water jet propulsion systems of High Speed Ships. This work has shown thatcurrent design guidance on scour protection is not appropriate for use on berths usedby High Speed Ships, that failure of these systems can occur rapidly andcatastrophically, and secondary effects from water jets may promote the failure ofquay walls. The scour protection system should comprise two individual elements, afilter layer and an armour layer. It has been found that systems involving individualisolated armour units are inappropriate and prone to failure and that shaped linkedarmour blocks need to be used. The loads on the armour layer were also found to beoscillatory and the materials used for both the armour and filter layers need to bedesigned for cyclic fatigue loading and fretting. Water jets are also capable ofreducing the strength of permeable, seabed strata.
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