Embedded rocking measurement of single layer armour units: Development and first results

Daan Houtzager, Bas Hofland, Ganga Caldera, Cock van der Lem, Marcel van Gent, Pieter Bakker, Alessandro Antonini

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

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Randomly placed breakwater armour units under wave loading can sometimes start rocking, which can lead to breakage of armour units. This failure mechanism can especially become important for single layer randomly placed armour units for which full displacement of units will only happen at higher stability numbers compared to older types of units, and where unit breakage can more easily lead to progressive damage to the armour layer. However, unlike older types of units, hardly any quantitative information is available on the impact velocities, and the number of impacts is mostly assessed using somewhat subjective visual observations. In design the observed number of rocking units is limited to the amount of visually observed rocking units. Hence a good quantification of impact velocities could lead to a more optimal design. This paper describes the further development of embedded rocking sensors to measure the motions of individual smart armour units. Multiple smart rocking sensors have been applied in a physical model of a breakwater and measurements were collected to determine the number of impacts and impact velocity of the armour units. The results have been compared to visual observations and the first results will be presented. It is concluded that the new technique can be used to obtain much more information on rocking, including impact velocities, and that more rocking occurs than is observed visually.
Original languageEnglish
Title of host publicationProcedings ICE Breakwaters conference 25-27 April 2023
PublisherInstitution of Civil Engineers
Number of pages13
Publication statusPublished - 2023
EventICE Breakwaters 2023: Coasts, Marine Structures and Breakwaters - Portsmouth Marriott Hotel, PO6 4SH, Portsmouth, United Kingdom
Duration: 25 Apr 202327 Apr 2023


ConferenceICE Breakwaters 2023
Country/TerritoryUnited Kingdom
Internet address

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