scholarly journals THE EFFECT OF TWIT WEIGHTS OF ROCK AND FLUID ON THE STABILITY OF RUBBLE MOUND BREAKWATERS

1966 ◽  
Vol 1 (10) ◽  
pp. 57 ◽  
Author(s):  
Anton Brandtzaeg
Keyword(s):  
Model Tests ◽  
Design Formula ◽  
Variable Quantity ◽  
Current Design ◽  
Rubble Mound ◽  
The Stability ◽  
Rubble Mound Breakwaters

To study the effect of the specific weights of armour block material and fluid on the stability of rubble mound breakwaters a total of 110 model tests were made, with varying specific weights of armour and fluid, sizes of blocks and slopes of the breakwater face. The tests indicate that in cases where the specific weights deviate much from usual values, the current design formula (Eq. (1)) should be modified by entering a variable quantity,

Artificial Intelligence and Rubble-Mound Breakwater Stability

2012 ◽  
pp. 1499-1506
Author(s):  
Gregorio Iglesias Rodriguez ◽  
Alberte Castro Ponte ◽  
Rodrigo Carballo Sanchez ◽  
Miguel Ángel Losada Rodriguez
Keyword(s):  
Physical Model ◽  
Model Tests ◽  
Wave Action ◽  
Ann Model ◽  
Climate Conditions ◽  
Wave Flume ◽  
Physical Model Tests ◽  
Rubble Mound ◽  
The Stability ◽  
Rubble Mound Breakwaters

Breakwaters are coastal structures constructed to shelter a harbour basin from waves. There are two main types: rubble-mound breakwaters, consisting of various layers of stones or concrete pieces of different sizes (weights), making up a porous mound; and vertical breakwaters, impermeable and monolythic, habitually composed of concrete caissons. This article deals with rubble-mound breakwaters. A typical rubble-mound breakwater consists of an armour layer, a filter layer and a core. For the breakwater to be stable, the armour layer units (stones or concrete pieces) must not be removed by wave action. Stability is basically achieved by weight. Certain types of concrete pieces are capable of achieving a high degree of interlocking, which contributes to stability by impeding the removal of a single unit. The forces that an armour unit must withstand under wave action depend on the hydrodynamics on the breakwater slope, which are extremely complex due to wave breaking and the porous nature of the structure. A detailed description of the flow has not been achieved until now, and it is unclear whether it will be in the future in view of the turbulent phenomena involved. Therefore the instantaneous force exerted on an armour unit is not, at least for the time being, amenable to determination by means of a numerical model of the flow. For this reason, empirical formulations are used in rubble-mound design, calibrated on the basis of laboratory tests of model structures. However, these formulations cannot take into account all the aspects affecting the stability, mainly because the inherent complexity of the problem does not lend itself to a simple treatment. Consequently the empirical formulations are used as a predesign tool, and physical model tests in a wave flume of the particular design in question under the pertinent sea climate conditions are de rigueur, except for minor structures. The physical model tests naturally integrate all the complexity of the problem. Their drawback lies in that they are expensive and time consuming. In this article, Artificial Neural Networks are trained and tested with the results of stability tests carried out on a model breakwater. They are shown to reproduce very closely the behaviour of the physical model in the wave flume. Thus an ANN model, if trained and tested with sufficient data, may be used in lieu of the physical model tests. A virtual laboratory of this kind will save time and money with respect to the conventional procedure.

scholarly journals ON THE STABILITY OF RUBBLE-MOUND BREAKWATERS Jose Joaquim

2011 ◽  
Vol 1 (7) ◽  
pp. 34
Author(s):  
Jose Joaquim Reis De Carvalho ◽  
Daniel Vera-Cruz
Keyword(s):  
Model Tests ◽  
Scale Model ◽  
Small Scale ◽  
Existing Structures ◽  
Rubble Mound ◽  
The Stability ◽  
Steep Slopes ◽  
Rubble Mound Breakwaters ◽  
The Waves ◽  
Level 2

Until the beginning of the second quarter of the present century, characteristics of rubble-mound breakwaters were determined by entirely empirical methods, although harbour engineers had been deal ing with this problem for man;> centuries. As a rule, designers merely compared the case under study with existing structures, prescribing sturdier breakwaters when those located in shores with a similar exposure had not withstood the most violent storms acting on them. The first empirical formula for breakwater design did not appear before 1933, but this and other similar formulas did not go beyond ordering and reducing the use of arbitrary methods in the choice of the elements making up the breakwater slopes more directly subjected to wave action; no sensible progress resulting there? From for the design methods of these structures.lt can even be stated that, due to the use of Iribarren's formula - the most widely used in Europe - which leads to the utilization of too heavy blocks placed in steep slopes (about ^/3)» a tendency began to be observed in designers, towards a considerable reduction of these slopes. Such a situation which, bearing in mind the knowledge available until about 10 years ago, was perfectly admissible, has been subjected to considerable changes thanks to: 1) the enormous advances achieved in the theoretical field, which placed our knowledge on the majority of Maritime Hydraulics subjects on a satisfactory level; 2) the invaluable help of small scale model tests, and3) our improved knowledge on natural phenomena which makes possible a comparatively satisfactory estimate of the characteristics of the waves to be anticipated at any point of the coast*We have merely to persevere along the route followed in the latter years in order to determine more accurate values fir the coefficients of the available formulas, representing the results obtained by means of graphs and tables, resorting for that purpose both to model tests and to a careful observation of the behaviour of completed structures throughout the world, above all those which underwent damages. On the other hand efforts should not be spared in concentrated attempts to discover new formulas as phenomena are, no doubt much too complex in the destruction of a breakwater to allow of a single satisfactory scheaetization. It should be borne in mind that, in spite of the laboratory tests recently carried out, our knowledges is limited to the area directly affected by the wave breaking and so a total knowledge of the stability of rubble-mound breakwaters lies still a long way ahead.

Artificial Intelligence and Rubble-Mound Breakwater Stability

2011 ◽  
pp. 144-150
Author(s):  
Gregorio Iglesias Rodriguez ◽  
Alberte Castro Ponte ◽  
Rodrigo Carballo Sanchez ◽  
Miguel Ángel Losada Rodriguez
Keyword(s):  
Physical Model ◽  
Model Tests ◽  
Wave Action ◽  
Ann Model ◽  
Climate Conditions ◽  
Wave Flume ◽  
Physical Model Tests ◽  
Rubble Mound ◽  
The Stability ◽  
Rubble Mound Breakwaters

Breakwaters are coastal structures constructed to shelter a harbour basin from waves. There are two main types: rubble-mound breakwaters, consisting of various layers of stones or concrete pieces of different sizes (weights), making up a porous mound; and vertical breakwaters, impermeable and monolythic, habitually composed of concrete caissons. This article deals with rubble-mound breakwaters. A typical rubble-mound breakwater consists of an armour layer, a filter layer and a core. For the breakwater to be stable, the armour layer units (stones or concrete pieces) must not be removed by wave action. Stability is basically achieved by weight. Certain types of concrete pieces are capable of achieving a high degree of interlocking, which contributes to stability by impeding the removal of a single unit. The forces that an armour unit must withstand under wave action depend on the hydrodynamics on the breakwater slope, which are extremely complex due to wave breaking and the porous nature of the structure. A detailed description of the flow has not been achieved until now, and it is unclear whether it will be in the future in view of the turbulent phenomena involved. Therefore the instantaneous force exerted on an armour unit is not, at least for the time being, amenable to determination by means of a numerical model of the flow. For this reason, empirical formulations are used in rubble-mound design, calibrated on the basis of laboratory tests of model structures. However, these formulations cannot take into account all the aspects affecting the stability, mainly because the inherent complexity of the problem does not lend itself to a simple treatment. Consequently the empirical formulations are used as a predesign tool, and physical model tests in a wave flume of the particular design in question under the pertinent sea climate conditions are de rigueur, except for minor structures. The physical model tests naturally integrate all the complexity of the problem. Their drawback lies in that they are expensive and time consuming. In this article, Artificial Neural Networks are trained and tested with the results of stability tests carried out on a model breakwater. They are shown to reproduce very closely the behaviour of the physical model in the wave flume. Thus an ANN model, if trained and tested with sufficient data, may be used in lieu of the physical model tests. A virtual laboratory of this kind will save time and money with respect to the conventional procedure.

scholarly journals THE STABILITY OF RUBBLE MOUND BREAKWATERS AGAINST IRREGULAR WAVES

1966 ◽  
Vol 1 (10) ◽  
pp. 54 ◽  
Author(s):  
Torkild Carstens ◽  
Alf Torum ◽  
Anton Tratteberg
Keyword(s):  
Wave Spectrum ◽  
Model Tests ◽  
Irregular Waves ◽  
Regular Waves ◽  
Destructive Effect ◽  
Wave Channel ◽  
Stability Data ◽  
Rubble Mound ◽  
The Stability ◽  
Rubble Mound Breakwaters

Through extensive model tests with rubble mound breakwaters conducted in many laboratories in recent years design criteria and stability data have been collected. To our knowledge such data have been based on tests with regular waves only. It has been more or less accepted that the destructive effect of a train of regular waves corresponds to a confused sea with a significant wave height equal to the height of the regular waves. At the Rxver and Harbour Research Laboratory at the Technical University of Norway a new wave channel has been equipped with a programmed wave generator which can produce irregular waves wxth any wanted wave spectrum. This paper deals with model tests of the stability of rubble mound breakwaters against irregular waves as compared with regular waves.

scholarly journals STABILITY OF HIGH DENSITY CUBES IN RUBBLE MOUND BREAKWATERS

2020 ◽  
pp. 4
Author(s):  
Yalcin Yuksel ◽  
Marcel van Gent ◽  
Esin Cevik ◽  
H. Alper Kaya ◽  
Irem Gumuscu ◽  
...  
Keyword(s):  
Relative Density ◽  
Slope Angle ◽  
High Density ◽  
Experimental Results ◽  
Normal Density ◽  
Stability Number ◽  
Damage Initiation ◽  
Rubble Mound ◽  
The Stability ◽  
Rubble Mound Breakwaters

The stability number for rubble mound breakwaters is a function of several parameters and depends on unit shape, placing method, slope angle, relative density, etc. In this study two different densities for cubes in breakwater armour layers were tested to determine the influence of the density on the stability. The experimental results show that the stability of high density blocks were found to be more stable and the damage initiation for high density blocks started at higher stability numbers compared to normal density cubes.

scholarly journals Correction: Eldrup, M.R., et al. Stability of Rubble Mound Breakwaters—A Study of the Notional Permeability Factor, based on Physical Model Tests. Water 2019, 11, 934

Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2483
Author(s):  
Mads Røge Eldrup ◽  
Thomas Lykke Andersen ◽  
Hans Falk Burcharth
Keyword(s):  
Physical Model ◽  
Model Tests ◽  
Permeability Factor ◽  
Physical Model Tests ◽  
Rubble Mound ◽  
Rubble Mound Breakwaters

The authors wish to make the following corrections to this paper [...]

scholarly journals Stability of Rubble Mound Breakwaters—A Study of the Notional Permeability Factor, Based on Physical Model Tests

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 934 ◽  
Author(s):  
Mads Røge Eldrup ◽  
Thomas Lykke Andersen ◽  
Hans Falk Burcharth
Keyword(s):  
Physical Model ◽  
Slope Angle ◽  
Model Tests ◽  
Permeability Factor ◽  
Physical Model Tests ◽  
Stability Model ◽  
The Stability ◽  
Rubble Mound Breakwaters ◽  
Layer Composition

The Van der Meer formulae for quarry rock armor stability are commonly used in breakwater design. The formulae describe the stability as a function of the wave characteristics, number of waves, front slope angle and rock material properties. The latter includes a so-called notional permeability factor characterizing the permeability of the structure. Based on armor stability model tests with three armor layer compositions, Van der Meer determined three values of the notional permeability. Based on numerical model results he added for a typical layer composition one more value. Based on physical model tests, the present paper provides notional permeability factors for seven layer compositions of which two correspond to the compositions tested by Van der Meer. The results of these two layer compositions are within the scatter of the results by Van der Meer. To help determination of the notional permeability for non-tested layer compositions, a simple empirical formula is presented.

scholarly journals TOE BERM DESIGN FOR RUBBLE-MOUND BREAKWATERS: EXAMPLE OF THE SAFI POWER PLANT PROJECT

2017 ◽  
pp. 34
Author(s):  
COUTOSTHEVENOT Marie ◽  
HONG Kyung-Wook
Keyword(s):  
Power Plant ◽  
Physical Model ◽  
Design Feature ◽  
Breaking Waves ◽  
Model Tests ◽  
Construction Methods ◽  
Physical Model Tests ◽  
Rubble Mound ◽  
Hydraulics Laboratory ◽  
Rubble Mound Breakwaters

DAEWOO E&C (Engineering & Construction) is in charge constructing a new 1320 MW coal-fired power plant located approximately 15 km south-west of the city of Safi in Morocco. ARTELIA Eau & Environnement was appointed by the Contractor to perform the hydraulic design review of the rubble-mound breakwaters protecting the intake and outfall. The toe berm is a key design feature of rubble-mound breakwaters built in breaking conditions, since it helps to support the armour layer and protect the structure from potential scour-induced damage. The initial toe berm design was based on Van Der Meer’s empirical formula (1998). Due to the very shallow water conditions, the toe design was verified through physical model tests (2D and 3D) in ARTELIA’s hydraulics laboratory located in Pont-de-Claix, near Grenoble (France). The physical model tests demonstrated that the toe berm (6t rocks, 3:1 slope) was not stable at key singular locations, namely roundheads and roots, where direct impacts of breaking waves caused severe damage. Given the site conditions and the construction methods, the usual solutions consisting in increasing the rock size and/or placing the toe berm in a trench had to be ruled out. It was hence decided to reinforce the toe with artificial blocks and to use rectangular concrete blocks with holes. These blocks reduced the anti-stabilizing pressure difference between the top and bottom of the blocks (Tanimoto et al., 1996) and drag force due to the considerable current. They are more usually used at the toe of vertical caissons.

scholarly journals A SIMPLE MATHEMATICAL MODEL OF WAVE MOTION ON A RUBBLE MOUND BREAKWATER SLOPE

2011 ◽  
Vol 1 (8) ◽  
pp. 26
Author(s):  
Anton Brandtzaeg
Keyword(s):  
Mathematical Model ◽  
Wave Motion ◽  
Point Of View ◽  
Glass Panel ◽  
Wave Channel ◽  
First Approximation ◽  
Rubble Mound ◽  
The Stability ◽  
Rubble Mound Breakwaters ◽  
Made In

In the improvement of design criteria for the layer of cover blocks on rubble mound breakwaters important advance has been made in recent years (l), (2), (3). Still, some points seem to require further study, among them the effect of the specific weights of block material and fluid on the stability of the cover. In this respect the magnitude of the fluid accelerations involved, of which little information is available may be of some importance. For evaluation of the acceleratic as well as for other purposes, a roughly approximate mathematic description of the motion of the water rushing up and down the breakwater front may be of some use. This motion certainly is neither steady nor uniform. Visual and photographic observation through the glass panel a wave channel seems to indicate, however, that unsteadiness the more important characteristic of the motion during the up and downrush proper. It seems reasonable, therefore, to att€ a first approximation to a description of the motion by neglecting, to a certain extent, its non-uniformity. Necessarily, the same time also the requirement of continuity must be partly disregarded. In the following a mathematical model based on this point of view is presented for consideration. It is believed that by means of this model values of displacements, velocity and accelerations can be calculated, which may reasonably be considered as useful, although quite rough, approximations t< the actual values. For a few particular cases, experimental evidence is reported. The model has reference only to the up- and downrush proper, that is, to the motion of the water above some limit level, at or somewhat below the Still Water Line (referred t< hereafter as the StflL). The motion below this level, where tl downrush meets the oncoming next wave, could hardly be conee of as being uniform.

Sign in / Sign up

Export Citation Format

Share Document