Since the publication of the report of MarCom Working Group 21 (?Guidelines for the Design and Construction of Flexible Revetments incorporating Geotextiles in the Marine Environment?) in 1992, there has been much development in the design rules for block revetments. Extensive international study has been conducted on the study of run-up and overtopping, while specific research on the stability of placed blocks has been carried out mainly in The Netherlands. Therefore, PIANC is seeking an update of the WG 21 report regarding the section on pattern placed block revetments. A publication written in Dutch on the design of block revetments [Flikweerd, 2003] and recent reports from Deltares (mainly authored by Klein Breteler) have been extensively used in the creation of this report. Unfortunately, at this time no English translation is available of these publications. A list of these documents is given in the bibliography at the end of this report and on the PIANC website. rn
rnIn general the amount of material to be used in a pattern placed block revetment is less than in a riprap revetment; however, placing blocks is more labour-intensive. This is a specific advantage for countries with a large inexpensive labour force. In China, Vietnam and Bangladesh these are very common constructions.rn
