scholarly journals IRREGULAR WAVE TESTS FOR COMPOSITE BREAKWATER FOUNDATIONS

1982 ◽  
Vol 1 (18) ◽  
pp. 128 ◽  
Author(s):  
Katsutoshi Tanimoto ◽  
Tadahiko Yagyu ◽  
Yoshimi Goda
Keyword(s):  
Wave Height ◽  
Significant Wave Height ◽  
Irregular Waves ◽  
Stability Number ◽  
Regular Waves ◽  
Significant Wave ◽  
Irregular Wave ◽  
Concrete Blocks ◽  
Rubble Mound ◽  
The Stability

The stability of armor units for the rubble mound foundations of composite breakwaters has been investigated under the action of irregular waves. The tests establish that irregular waves are more destructive than regular waves, when the height of regular waves is set equal to the significant wave height. The stability number, defined by Hudson, for quarry stones and concrete blocks with simple shapes is formulated on the basis of irregular wave tests. The stability number is expressed by two parameters of h'7/7]/3 and K, where h' is the crest depth of the rubble mound foundation, #1/3 is the design significant wave height, and K is a parameter for the combined effects of the relative water depth and the relative berm width of the rubble mound foundation to the wavelength. The design mass of armor units can be calculated by the stability equation with the stability number. The application of the proposed method to the results of the irregular wave tests demonstrates that the damage percent for the quarry stones is at most 3.5% at the design condition and the damage progresses rather gradually for the action of higher waves. On the other hand, the damage of the concrete blocks almost jumps beyond the design wave height. In particular, the drastic damage is often caused in the case of high rubble mound foundations. The proposed method is confirmed, however, to be applicable for the ordinary low mound foundations with a sufficient safety.

scholarly journals OVERTOPPING OF RUBBLE-MOUND BREAKWATERS BY IRREGULAR WAVES

1976 ◽  
Vol 1 (15) ◽  
pp. 157
Author(s):  
Yvon Ouellet ◽  
Pierre Eubanks
Keyword(s):  
Wave Train ◽  
The Other ◽  
Irregular Waves ◽  
Regular Wave ◽  
Regular Waves ◽  
Irregular Wave ◽  
Wave Trains ◽  
Rubble Mound ◽  
The Stability ◽  
Rubble Mound Breakwaters

This paper describes the results of an experimental study on the effect of waves on rubble-mound breakwaters, wave transmission subsequent to wave overtopping, the stability of the three sides subjected to wave action and the effect of the breakwaters on waves. Two different rubble-mound breakwaters were tested, i. e. one with a rigid impermeable crest and the other with a flexible permeable crest. Tests were performed with both regular and irregular wave train systems. To obtain the simulated irregular wave trains, four theoretical spectra were chosen: Neumann, Bretschneider, Moskowitz, and Scott. Results obtained from tests with irregular wave trains were compared to those obtained from tests with regular wave trains. It was found that more information was obtained on the behaviour of the structure when it was submitted to the attack of irregular waves than when submitted to regular waves, and that the use of irregular wave trains gave more interesting results.

Physical and Numerical Investigations on Wave Run-Up and Dissipation under Breakwater with Fence Revetment

2021 ◽  
Vol 9 (12) ◽  
pp. 1355
Author(s):  
Enjin Zhao ◽  
Lin Mu ◽  
Zhaoyang Hu ◽  
Xinqiang Wang ◽  
Junkai Sun ◽  
...  
Keyword(s):  
Wave Height ◽  
Water Depth ◽  
Significant Wave Height ◽  
Irregular Waves ◽  
Structure Stability ◽  
Wave Impact ◽  
Significant Wave ◽  
Tide Level ◽  
Run Up ◽  
The Impact

Revetment elements and protective facilities on a breakwater can effectively weaken the impact of waves. In order to resist storm surges, there is a plan to build a breakwater on the northern shore of Meizhou Bay in Putian City, China. To better design it, considering different environmental conditions, physical and numerical experiments were carried out to accurately study the effects of the breakwater and its auxiliary structures on wave propagation. In the experiments, the influence of the wave type, initial water depth, and the structure of the fence plate are considered. The wave run-up and dissipation, the wave overtopping volume, and the structure stability are analyzed. The results indicate that the breakwater can effectively resist the wave impact, reduce the wave run-up and overtopping, and protect the rear buildings. In addition, under the same still water depth and significant wave height, the amount of overtopped water under regular waves is larger than that under irregular waves. With the increase of the still water depth and significant wave height, the overtopped water increases, which means that when the storm surge occurs, damage on the breakwater under the high tide level is greater than that under the low tide level. Besides, the fence plate can effectively dissipate energy and reduce the overtopping volume by generating eddy current in the cavity. Considering the stability and the energy dissipation capacity of the fence plate, it is suggested that a gap ratio of 50% is reasonable.

scholarly journals IRREGULAR WAVE ATTACK ON A DOLOS BREAKWATER

1974 ◽  
Vol 1 (14) ◽  
pp. 98
Author(s):  
C. Campos Morais
Keyword(s):  
Wave Height ◽  
Significant Wave Height ◽  
Scale Model ◽  
Two Dimensional ◽  
Regular Wave ◽  
Significant Wave ◽  
Irregular Wave ◽  
Wave Flume ◽  
General Cargo ◽  
Is Design

The paper deals with two-dimensional tests on a scale model of a dolos breakwater. It is related with the construction of a large harbour at Sines for tankers with up to 1 million dwt, ore ships with up to 300,000 dwt, general cargo, etc. The main breakwater is design ed with 40 t dolos, in order to withstand waves with up to 1 1 m significant wave height(100 years return period). Considerations on wave data and on modelling the spectrum ( Pierson-Moskowitz ) precede the presentation of three sets of tests on LNEC's irregular wave flume. Main results are compared with those from regular wave tests. The most important conclusions are stressed: influence of pla_ cement on dolos damages, irrelevance of maintenance, importance of the singular zone of the dolos support base, disadjustment of Hudson's formula for calculation of dolos weight using H as significant wave height,and importance of individual movements for the risk of breaking of individual blocks.

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 STABILITY ANALYSIS FOR A RUBBLE-MOUND FOUNDATION THROUGH IRREGULAR WAVE TEST

1982 ◽  
Vol 1 (18) ◽  
pp. 127
Author(s):  
Masato Yamamoto ◽  
Tsutomu Asakawa
Keyword(s):  
Stability Analysis ◽  
Wave Height ◽  
Surf Zone ◽  
Average Height ◽  
Critical Stability ◽  
Cover Layer ◽  
Irregular Wave ◽  
Design Purpose ◽  
Rubble Mound ◽  
The Stability

Irregular wave tests have been conducted to research into the stability characteristics of armor units for a rubble foundation of a composite breakwater. A cover layer to protect the rubble foundation from erosion had two layers of tetrapods. Waves higher than H]_/]_Q (the average height of the highest 10% of all waves) caused damage to armor units at the point of critical stability. This suggested that wave height changes in the surf zone should be taken into consideration for design purpose.

scholarly journals STABILITY OF RUBBLE MOUND BREAKWATERS IN SHALLOW WATER AND SURF ZONE : AN EXPERIMENTAL STUDY

2012 ◽  
Vol 1 (33) ◽  
pp. 85
Author(s):  
Guirec Prevot ◽  
Olivier Boucher ◽  
Maryline Luck ◽  
Michel Benoit
Keyword(s):  
Shallow Water ◽  
Wave Height ◽  
Significant Wave Height ◽  
Characteristic Wave ◽  
Significant Wave ◽  
Wave Parameters ◽  
Rubble Mound ◽  
Wave Conditions ◽  
Wave Models ◽  
Rubble Mound Breakwaters

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 regarded as being of Rayleightype) and in the shape of the wave spectrum. This, combined with the fact that most of the models used nowadays for nearshore wave propagation are spectral wave models (e.g. SWAN, TOMAWAC, etc.) and thus provide spectral parameters as output (typically the spectral significant wave height Hm0 and the peak period Tp or the mean energetic period Tm-1,0) has raised the question of which characteristic wave parameter should be used in stability formulas for rubble-mound breakwaters in shallow water. This has led to the consideration of more representative wave parameters such as H2% or Tm-1,0 which are sometimes less accessible from existing wave database or numerical modelling studies. The objective of the present study is to review and compare several available methods to calculate armour stone weight in shallow waters, and to provide some insight into the applicability and limitations of these methods based on a series of wave flume experiments.

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.

Sign in / Sign up

Export Citation Format

Share Document