Breakwaters and coast defences: Specification and measurement of rock for coastal structures and breakwaters

Significant developments have taken place recently in the understanding of how coastal rock structures respond to incident wave (and tidal) conditions and, in turn, influence those conditions. In designing and placing such structures, however, the civil engineer also needs to take account of such practicalities as: the likely 'intrinsic' properties of the in-situ rock in the quarry; realistic ranges on the 'manufactured' properties of the rock after winning; and the 'as-constructed' properties and profiles achievable and necessary. The recently published CIRIA/CUR Manual on the use of rock in coastal and shoreline engineering draws together all such information in an accessible and 'user-friendly' manner to assist in efficient, economic and environmentally attractive design. It also seeks to limit disputes by giving standardized approaches to specification and measurement for payment. Based on the Manual, this Technical Note summarizes some of the key data and factors which the engineer should address.