Damage in Rubble Mound Breakwaters. Part I: Historical Review of Damage Models (original) (raw)
Related papers
Damage Analysis for Rubble-Mound Breakwaters
Coastal Engineering 1994, 1995
Storm damage to rubble-mound structures can range from the piece-wise removal of individual armour stones to the large-scale sliding of the entire armour layer. This paper presents an overview of qualitative and quantitative descriptions of various types of armour layer damage due to wave action. This work is based on a series of large-scale physical models of revetment stability. The discussion includes methods for measuring the change in profile and the use of the normalized area eroded, S. A new parameter, d c is introduced as a measure of the minimum depth of cover remaining on the structure. An analysis method is presented which predicts the armour layer's factor of safety against sliding.
Journal of Marine Science and Engineering, 2020
Damage in rubble mound breakwaters has been addressed for more than 80 years and, as reported in “Part I: Historical review of damage models”, a considerable number of hydraulic instability models have been proposed up to date. Most of them were developed from small-scale physical tests, based on damage descriptors not always parameterized nor measured in the same way, which indeed complicates the comparison and reproducibility from different experimental data sources. The latter is increased by the lack of a standardized methodological approach inside an experimental and measuring process that involves many sources of uncertainty. Currently, the latest innovations applicable to damage measurement, together with the growing demand of reliable decision-making tools for conservation/maintenance strategies and structural/operational risk management, venture an upcoming proliferation of prototype monitoring, as well as new approaches aimed to characterize the stochastic nature of damage...
The long-term failure of rubble mound breakwaters
Mediterranee Revue Geographique Des Pays Mediterraneens Journal of Mediterranean Geography, 2014
Rubble mound breakwaters have probably existed for around 3000 years and modern coastal engineers still build them to create harbours sheltered from wave action. Some ancient breakwaters are still well preserved today, while many others are now eroded and submerged as a consequence of thousands of years of storms and wave activity. The present study aims to find a simple relationship between the governing parameters (water depth, structure height, stone size) and the equilibrium position of the crest of rubble mound breakwaters subject to repeated wave attack in breaking wave conditions over many centuries. It is concluded that an initially undersized emerging rubble mound breakwater will be eroded by the waves and finally reduced to a submerged breakwater whose height above the sea bed depends on its stone size and on the water depth.
Wave height parameter for damage description of rubble-mound breakwaters
Coastal Engineering, 2006
In this paper it will be shown that the wave height parameter H 50 , defined as the average wave height of the 50 highest waves reaching a rubble-mound breakwater in its useful life, can describe the effect of the wave height on the history of the armor damage caused by the wave climate during the structure's usable life.
2018
Usually, physical model tests support the design of breakwaters considering different<br>incident wave conditions, including extreme events. This paper describes two-dimensional physical<br>model tests of a rock armour breakwater, performed at LNEC´s experimental facilities, under the<br>framework of the HYDRALAB+ project. The goal of the present work is to evaluate damage<br>evolution under wave conditions resulting from future climate change scenarios. Test results are<br>presented in terms of the non-dimensional damage parameter (S) and of the percentage of displaced<br>armour units (D). The data analysis is focused on the cumulative damage progression related with<br>wave parameters as Hmax and H2%, for the imposed storm sequences. The use of the stability number<br>(Ns), considering both H=Hs and H=H2% revealed a good agreement in order to characterize its<br>relationship with damage evolution. On the other hand, the use of ...
Stability of Rubble Mound Breakwaters in Shallow Water and Surf Zone : An Experimental Study
Coastal Engineering Proceedings, 2012
Rubble-mound breakwaters are often pre-designed with empirical formulae allowing the estimation of armour stone size or weight, taking into account the wave conditions (mainly a characteristic wave height and a characteristic period), the type and density of stone or block used, the slope of the mound, the acceptable level of damage, etc. In deep water conditions, the existing formulas are rather well established (e.g. Hudson and Van der Meer formulas among others). They use as input data wave parameters that are well defined (e.g. the significant wave height H1/3 or sometimes the height H1/10) and easily accessible, from in situ measurements or from numerical wave models. In shallow water however, and in particular in breaking wave conditions (where most of the small breakwaters are built), a number of physical processes (refraction, shoaling and breaking) significantly modify the incoming waves. They also lead to changes in the wave height distribution (which can no longer be rega...
Stability of Rubble Mound Breakwaters Against Solitary Waves
Coastal Engineering Proceedings, 2012
No formulas currently exist to design armour units against tsunami attack. To develop such formulae, laboratory experiments were carried out to clarify the failure mechanism of these types of structures. Also, the behavior of armour units against real cases of tsunami attack during the 2011 Tohoku tsunami were evaluated. Both the results of the laboratory experiments and the breakwaters studied in the field where then analyzed in terms of well established formulas such as that of Van der Meer or Hudson. The design of structures that only fail partially during a given tsunami event (“resilient” or “tenacious” structures) should be prioritized in future counter-measures, and in order to make it possible to construct such structures a modification of the Hudson formula for their design is proposed.
Analysis and Design of Refurbishment for Unusual Damage to a Rubble Mound Breakwater
Coastal Structures 2011, 2012
ABSTRACT A relatively simple rubble mound breakwater has been used to protect a large lagoon, itself then progressively filled by dry waste materials, some (potentially) sensitive to possible erosion. The breakwater is exposed to an extreme tidal range (~12m) and wave attack can exceed Hs≈ 8m at 1 :200 year return. Since construction, a part of the breakwater length has shown signs of unusual damage. This paper describes analysis of that damage, the derivation of Joint Probability Analysis conditions, and the development of refurbishment options taking account of current conditions, and potential future changes to waves and water levels.
Damage progression in rubble-mound breakwaters scale model tests under different storm sequences
2018
This paper describes the 2D physical model tests performed for a rock armour breakwater at LNEC ́s facilities, under the framework of the HYDRALAB+ project. The aim of the present work was to evaluate damage evolution under different approaches of storm sequences, corresponding to different climate change scenarios. The tested wave conditions intended to simulate different sequences of water levels (low water and high water), significant wave heights and peak periods. Damage evaluation was based on the traditional visual method and on stereo-photogrammetric techniques. Results in terms of the non-dimensional damage parameter, the non-dimensional damage depth and the percentage of displaced armour units are compared for the different storm sequences. KEWORDS: Physical model, Damage evolution, Climate change, Storm sequences
Coastal Engineering, 1979
. The joint effect of the wave height and period on the stability of rubble mound breakwaters using Iribarren's number. Coastal Eng., 6: 77-96. A new analysis of the experimental results of Iribarren is undertaken. Using a single parameter, Q, the stability of a rubble mound breakwater is studied. This parameter shows a strong correlation with Iribarren's number ~ = tana/~/(H/L o ) and thus manifests among others the effect of the wave period on the stability. A function, Q = f (~), which includes two coefficients which depend on slope and type of armour units, is proposed to evaluate the response of a rubble mound breakwater to the action of regular waves. The new formula is applied to tests performed by Hudson, and Ahrens and Mc Cartney with satisfactory results. Finally an interaction curve is presented which defines stability in a wave height-wave period diagram for a given rubble mound breakwater.