scholarly journals STABILITY OF INTERLOCKING ARMOUR UNITS ON A BREAKWATER CREST

2012 ◽  
Vol 1 (33) ◽  
pp. 11 ◽  
Author(s):  
Ilse Van den Bosch ◽  
Erik Ten Oever ◽  
Pieter Bakker ◽  
Markus Muttray
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Packing Density ◽  
Single Layer ◽  
Hydraulic Model ◽  
Model Tests ◽  
Wave Steepness ◽  
Design Wave Height ◽  
The Stability ◽  
Hydraulic Stability

The hydraulic stability of single layer, interlocking armour units on low crested and submerged breakwaters was investigated in 2D hydraulic model tests. Displacements of armour units and rocking were monitored and have been applied as indicators for the armour layer stability on the crest, front and rear slope. The effect of freeboard, packing density and wave steepness on the armour layer stability have been investigated. The stability of interlocking concrete armour units on low crested and submerged structures is qualitatively different from rock armour. About 40% to 50% larger armour units are required on the seaward slope and crest of low crested structures (as compared to conventional high crested breakwaters). About 35% larger armour units are required on the rear slope. Larger armour units are not required on submerged breakwaters if the water depth on the crest exceeds 50% of design wave height.

scholarly journals HYDRAULIC STABILITY AND OVERTOPPING PERFORMANCE OF A NEW TYPE OF REGULAR PLACED ARMOR UNIT

2018 ◽  
pp. 111
Author(s):  
Bas Reedijk ◽  
Tamara Eggeling ◽  
Pieter Bakker ◽  
Robert Jacobs ◽  
Markus Muttray
Keyword(s):  
Wave Height ◽  
Single Layer ◽  
Model Tests ◽  
Roughness Coefficient ◽  
Design Wave Height ◽  
Wave Heights ◽  
New Type ◽  
Adverse Influence ◽  
2D And 3D ◽  
Hydraulic Stability

The XblocPlus is a new type of interlocking single layer armour units that is placed with uniform orientation. This is novel and different from all other single layer, interlocking armouring systems. The hydraulic stability of the XblocPlus breakwater armour unit was tested in 2D and 3D hydraulic model tests. Wave overtopping tests were performed to determine the roughness coefficients of the EurOtop overtopping formula for the XblocPlus. Model tests on a rubble mound breakwater with XblocPlus armour included 2D tests with a 1:30 seabed slope and with 1:2 and 3:4 breakwater slopes and 3D model tests with a flat seabed and with a 3:4 breakwater slope. Wave heights up to 150% of the design wave height were tested in the 2D tests and up to 200% with wave directions 0° to 60° in the 3D tests. No armour unit displacements were observed in 2D tests with 1:2 slope. In the 2D tests with 3:4 slope one armour unit was displaced when the wave height reached 159% of the design wave height. No damage to the XblocPlus armour layer was observed in the 3D tests. A roughness coefficient of 0.45 was deduced from overtopping tests with wave heights of 60% to 100% of the design wave height. The model test results indicate little or no influence of wave steepness on XblocPlus stability and no adverse influence of wave obliquity while the seabed slope in front of the breakwater may have some impact on the XblocPlus armour layer stability.

scholarly journals USE OF SINGLE LAYER CONCRETE ARMOUR UNITS AS TOE REINFORCEMENT

2012 ◽  
Vol 1 (33) ◽  
pp. 48
Author(s):  
Martin Young ◽  
John Hayman-Joyce ◽  
Seok Hyeon Kim
Keyword(s):  
Water Depth ◽  
Packing Density ◽  
Single Layer ◽  
Hydraulic Model ◽  
Model Testing ◽  
Environmental Constraints ◽  
Plane Compression ◽  
A Site ◽  
Hydraulic Stability

Detailing and optimization of the toe reinforcement is presented as a case study from the construction of the 5.2km long main breakwater for the new Colombo South Harbour in 18m water depth. During the breakwater design the environmental constraints on supply of large rock armour were recognized, and CORE-LOC™ single layer concrete armour units were selected for the primary armour protection. During construction, supply of relatively small quantities of 8-12t rock for use in the toe reinforcement became an issue, and use of CORE-LOC™ units placed on the flat rock armour apron as an alternative to rock armour toe reinforcement was investigated and implemented. This use is unusual as there is no in-plane compression between units as found when they are placed on the slope. A site based prototype scale trial was conducted to evaluate placing method and criteria, and an “alternate opposing cannon” pattern placement, in rows going seaward from the primary armour, was successful. Packing density and unit spacing is the same as for the primary armour. Hydraulic stability of this alternative toe reinforcement was verified in 2D physical hydraulic model testing.

scholarly journals HYDRAULIC STABILITY AND OVERTOPPING PERFORMANCE OF A NEW TYPE OF REGULAR PLACED ARMOR UNIT

2018 ◽  
Vol 1 (36) ◽  
pp. 54
Author(s):  
Bas Reedijk ◽  
Tamara Eggeling ◽  
Pieter Bakker ◽  
Robert Jacobs ◽  
Markus Muttray
Keyword(s):  
Failure Mechanisms ◽  
Single Layer ◽  
Model Tests ◽  
Roughness Coefficient ◽  
Regular Pattern ◽  
Wave Loading ◽  
The World ◽  
New Type ◽  
The Stability ◽  
Hydraulic Stability

Single layer, randomly placed, interlocking concrete units are widely used for the protection of exposed breakwaters. Based on 15 years of experience with Xbloc projects around the world, DMC started the development of an armour unit called XblocPlus. XblocPlus is a single layer concrete unit which is placed in a regular pattern. An essential part of this development were hydraulic model tests in 2D and in 3D to determine the hydraulic stability under wave loading and the overtopping volumes for the new units. These studies and the results regarding the stability, failure mechanisms and roughness coefficient are described in this paper.

Application of Roughening with the Grass Cushions in the Hydraulic Model of Comprehensive Harness of Qian'an Reach of Luan River

2013 ◽  
Vol 405-408 ◽  
pp. 2096-2099
Author(s):  
Hai Jing Zhao ◽  
Ya Dong Jin ◽  
Jun Liu
Keyword(s):  
Water Depth ◽  
Hydraulic Model ◽  
Model Tests ◽  
Test Area ◽  
Comprehensive Model ◽  
Hydraulic Models

Restricted by such factors as the size of test area, amount of work and water depth of model, hydraulic models are often made into distorted patterns, whereas the distorted models demand for roughening usually. The hydraulic model of comprehensive harness of Qian'an Reach of Luan River requires big roughness that general roughening technologies cant meet, so the plastic grass cushions were introduced. The preliminary experiment in flume, the preliminary experiment of the comprehensive model and the verification experiment of the comprehensive model proved the feasibility of the technology of roughening with the grass cushions in hydraulic model tests.

Analysis and Applications of Second Order Models for Maximum Crest Height

2002 ◽  
Author(s):  
Harald E. Krogstad ◽  
Stephen F. Barstow
Keyword(s):  
Time Series ◽  
Wave Height ◽  
Water Depth ◽  
Second Order ◽  
Wave Steepness ◽  
Data Set ◽  
Wave Data ◽  
Definite Improvement ◽  
Crest Height

Expressions for the maximum crest height are reviewed and tested on data from five different sensors in the WACSIS data set. The overall agreement is good and the analysis supports that second order models give accurate expressions for the distribution of the maximum crest height for varying water depth and wave steepness. In the second part of the paper, the expressions are combined with the existing extreme crest and wave height framework and applied to sets of time series and long term wave data. It is concluded that the 2nd order models represent a definite improvement over earlier empirical parametrizations.

Analysis and Applications of Second-Order Models for Maximum Crest Height

2004 ◽  
Vol 126 (1) ◽  
pp. 66-71 ◽  
Author(s):  
Harald E. Krogstad ◽  
Stephen F. Barstow
Keyword(s):  
Time Series ◽  
Wave Height ◽  
Water Depth ◽  
Second Order ◽  
Wave Steepness ◽  
Data Set ◽  
Wave Data ◽  
Definite Improvement ◽  
Crest Height

Expressions for the maximum crest height are reviewed and tested on data from five different sensors in the WACSIS data set. The overall agreement is good and the analysis supports that second-order models give accurate expressions for the distribution of the maximum crest height for varying water depth and wave steepness. In the second part of the paper, the expressions are combined with the existing extreme crest and wave height framework and applied to sets of time series and long term wave data. It is concluded that the second-order models represent a definite improvement over earlier empirical parametrizations.

scholarly journals STABILITY OF RUBBLE MOUND BREAKWATER

1980 ◽  
Vol 1 (17) ◽  
pp. 120 ◽  
Author(s):  
J. Feuillet ◽  
M. Sabaton
Keyword(s):  
Wave Height ◽  
Breaking Waves ◽  
Random Waves ◽  
Regular Waves ◽  
T Wave ◽  
Design Wave Height ◽  
Storm Duration ◽  
Equivalent Wave ◽  
Rubble Mound ◽  
The Stability

The stability of a rubble mound breakwater section, with 3 in 2 armour slope, was tested under random waves attack. Tests analysis shows that the equivalent wave height characterizing the spectrum to be used in a stability formula elaborated with regular waves (for instance the Hudson's formula) is the upper twentieth height of the distribution for a storm duration of 6 hours. An analytical expression of the damage evolution as function of time modulates this choice according to the storm duration. The same rubble mound breakwater was also tested under the action of regular breaking waves. The damage was expressed in terms of the four following parameters : H0 : wave height T : wave period Dp : water depth at the toe of the structure Djj : breaker depth without the breakwater For a given wave height, the most important damage occur when : °b In this case the design wave height must be increased by about 30 % when using a stability formula elaborated for non breaking waves.

scholarly journals WAVE OVERTOPPING AT BERM BREAKWATERS IN LINE WITH EUROTOP

2012 ◽  
Vol 1 (33) ◽  
pp. 12 ◽  
Author(s):  
Sigurdur Sigurdarson ◽  
Jentsje W. Van der Meer
Keyword(s):  
Hydraulic Model ◽  
Model Tests ◽  
Wave Period ◽  
Wave Steepness ◽  
Wave Overtopping ◽  
Rubble Mound ◽  
Rubble Mound Breakwaters

The paper presents the development of a new overtopping formula for berm breakwaters. Overtopping data from hydraulic model tests of berm breakwaters have been gathered and reanalysed in line with the procedure in the EurOtop Manual. The data shows a clear dependency on wave period or wave steepness, which is in contrast to the main conclusion of the CLASH project and the EurOtop Manual for conventional rubble mound breakwaters. The formula is roughly validated on prototype performance.

scholarly journals DESIGNING BERM BREAKWATERS FOR DIFFERENT WAVE HEIGHTS AND DIFFERENT QUARRY YIELD

2017 ◽  
pp. 33
Author(s):  
Sigurdur Sigurdarson ◽  
Jentsje Van der Meer
Keyword(s):  
Wave Height ◽  
Initial Phase ◽  
Full Range ◽  
Stability Parameter ◽  
Design Rules ◽  
Design Wave Height ◽  
Final Design ◽  
Wave Heights ◽  
The Stability ◽  
Design Options

The paper demonstrates the use of the geometrical design rules for berm breakwaters in a potential project in Greenland. With practically no information about the sizes of armourstone that could be used for the design, the initial phase of the study looked at the full range of the stability parameter Hs/ΔDn50 of 1.7 to 3.0 for the design wave height of Hs=4.4 m. This corresponds to armourstone classes ranging from 5-15 t down to 1-3 t. Six different design options based on six different options for the largest stone class are compared. The final design then relies on the actual quarry yield, the total volume of material needed for the project and the construction equipment that can be brought to the site.

scholarly journals DAMAGE CRITERIA IN ROUNDHEADS ARMOURED WITH A SINGLE LAYER OF CUBIPOD ARMOR UNITS

2017 ◽  
pp. 13 ◽  
Author(s):  
José Sande ◽  
Enrique Peña ◽  
Enrique Maciñeira
Keyword(s):  
Active Zone ◽  
Sea Water ◽  
Single Layer ◽  
Relevant Parameter ◽  
Wave Steepness ◽  
Principal Parameter ◽  
Physical Model Tests ◽  
The Stability ◽  
Damage Criteria ◽  
Vertical Size

The present paper covers the analysis of damage in a single-layer roundhead armored with Cubipods. This study was carried through physical model tests. Firstly, the analysis of the damage in these structures has not been an intensive studied topic. It is normally defined when a piece doesn’t contribute in the stability on the single layer armor and, due to, a new damage criteria was proposed. In addition, vertical and sectorial size of active zone was defined. It could be possible defined three different phases in the evolution of damage due to the homogenous behavior for the roundhead. The most damage sector is 90-135º, and the neighbors, 45-90º and 135-180º, but damage in 45-90º is greater in frequency and value. Also, the dimensionless parameters of roundhead size (Rn, R/H and R/L) are involved in this phenomenon. Besides, the vertical size of active zone is defined in ±1.5Hs since sea water level (SWL), being the wave steepness is the principal parameter involved. It was proposed two level of damage: start of damage (D [%] =0.4) and failure (D [%] =11). Finally, it has been measure the reserve of stability. It is defined like the percentage of wave that the roundhead is able to resists between 2 levels of damage. This parameter allows analyzes the rigid behavior of the roundhead single layer armor. The value of this parameter, except one case, is RE [%] =9. It was conclude that wave steepness is a relevant parameter, when it increased the reserve is reduces.

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