Reduction of Wave Pressures on Vertical Seawall/Caissons Due to an Offshore Breakwater

2003 ◽  
Author(s):  
Muthukuru G. MuniReddy ◽  
Subramanian Neelamani
Keyword(s):  
Physical Model ◽  
Material Selection ◽  
Extreme Wave ◽  
Regular Waves ◽  
Wave Flume ◽  
Seaward Side ◽  
Fluid Mass ◽  
Physical Model Tests ◽  
Static Nature ◽  
Selection Of

Estimation of wave pressures on vertical impermeable caissons and seawall is needed to determine the dimensions and appropriate material selection of the structure. Reduction of extreme wave loadings (pressures) by constructing an offshore breakwater on seaward side of these structures is investigated. A series of physical model tests were carried out in a wave flume to examine the performance of the defense structure (offshore breakwater) in reducing the wave pressures on the seawall/caisson. Quasi-static nature of the wave pressures was observed due to piling-up of fluid mass behind the breakwater. The influence of the pool length on reduction of pressures on seawall/caisson is also investigated for regular waves.

scholarly journals Statistical Analysis of the Stability of Rock Slopes

2019 ◽  
Vol 7 (3) ◽  
pp. 60 ◽  
Author(s):  
Marcel van Gent ◽  
Ermano de Almeida ◽  
Bas Hofland
Keyword(s):  
Statistical Analysis ◽  
Physical Model ◽  
Model Tests ◽  
Water Levels ◽  
Test Series ◽  
Length Effect ◽  
Wave Flume ◽  
Physical Model Tests ◽  
Erosion Area ◽  
The Stability

Physical model tests were performed in a wave flume at Deltares with rock armoured slopes. A shallow foreshore was present. At deep water, the same wave conditions were used, but by applying different water levels, the wave loading on the rock armoured slopes increased considerably with increasing water levels. This allowed an assessment of the effects of sea level rise. Damage was measured by using digital stereo photography (DSP), which provides information on each individual stone that is displaced. Two test series were performed five times. This allowed for a statistical analysis of the damage to rock armoured slopes, which is uncommon due to the absence of statistical information based on a systematic repetition of test series. The statistical analysis demonstrates the need for taking the mean damage into account in the design of rock armoured slopes. This is important in addition to characterising the damage itself by erosion areas and erosion depths. The relation between damage parameters, such as the erosion area and erosion depth, was obtained from the tests. Besides tests with a straight slope, tests with a berm in the seaward slopes were also performed. A new method to take the so-called length effect into account is proposed to extrapolate results from physical model tests to real structures. This length effect is important, but is normally overlooked in the design of rubble mound structures. Standard deviations based on the presented model tests were used.

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 Separation of Long-Crested Nonlinear Bichromatic Waves into Incident and Reflected Components

2019 ◽  
Vol 7 (2) ◽  
pp. 39 ◽  
Author(s):  
Thomas Lykke Andersen ◽  
Mads R. Eldrup ◽  
Maria Clavero
Keyword(s):  
Physical Model ◽  
Nonlinear Waves ◽  
New Method ◽  
Regular Waves ◽  
Third Order ◽  
Reflected Waves ◽  
The Third ◽  
New Methods ◽  
Linear Waves ◽  
Physical Model Tests

Methods for the separation of long-crested linear waves into incident and reflected waves have existed for more than 40 years. The present paper presents a new method for the separation of nonlinear bichromatic long-crested waves into incident and reflected components, as well as into free and bound components. The new method is an extension of a recently proposed method for the separation of nonlinear regular waves. The new methods include both bound and free higher harmonics, which is important for nonlinear waves. The applied separation method covers interactions to the third order, but can easily be extended to a higher orders. Synthetic tests, as well as physical model tests, showed that the method accurately predict the bound amplitudes and incident and reflected surface elevations of nonlinear bichromatic waves. The new method is important in order to be able to describe the detailed characteristics of nonlinear bichromatic waves and their reflection.

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.

Research on Material Selection with Multi-Attribute Decision Method and G1 Method

2014 ◽  
Vol 952 ◽  
pp. 20-24 ◽  
Author(s):  
Xue Jun Xie
Keyword(s):  
Material Selection ◽  
Selection Process ◽  
Selection Problem ◽  
Topsis Method ◽  
Attribute Weight ◽  
Multi Attribute Decision Making ◽  
Judgment Matrix ◽  
Optimal Material ◽  
Selection Of ◽  
Better Than

The selection of an optimal material is an important aspect of design for mechanical, electrical, thermal, chemical or other application. Many factors (attributes) need to be considered in material selection process, and thus material selection problem is a multi-attribute decision making (MADM) problem. This paper proposes a new MADM method for material selection problem. G1 method does not need to test consistency of the judgment matrix. Thus it is better than AHP. In this paper, firstly, we use the G1 method to determine the attribute weight. Then TOPSIS method is used to calculate the closeness of the candidate materials with respect positive solution. A practical material selection case is used to demonstrate the effectiveness and feasibility of the proposed method.

Advantages in Environmental Compliance For Maritime Corrosion Control

2015 ◽  
Author(s):  
Eric Lethe
Keyword(s):  
Material Selection ◽  
Shop Floor ◽  
Chief Financial Officer ◽  
Successful Implementation ◽  
The Past ◽  
New Methods ◽  
Traditional Procedure ◽  
Environmentally Sound ◽  
A Company ◽  
Selection Of

The need for environmentally compliant processes and materials in the Painting Industry grows more pressing every day. As the need for these processes grows, so grows the confusion regarding the selection and implementation of these new methods and materials. In the past, price and traditional procedure were the only criteria by which a material was procured. Speed and compliance with Original Equipment Manufacturer specification governed how things were done on the shop floor. With the advent of the environmental regulations, processes are being examined all across the globe. In many of the larger companies, the chief environmental officer has as important a role as the comptroller or Chief Financial Officer. Environmental managers are often not chemists or line painters, and typically, the environmental manager is skilled only in the policies of waste disposal, spill clean up, or remediation. The methods whereby a company can minimize the generation of hazardous waste remain less familiar. Often the examination of possible alternate techniques and materials are left for the last minute, or are conducted by personnel who are unfamiliar with how to make changes work. This is usually a recipe for failure in the implementing of anything new. This paper will suggest methods for selection of alternative products and processes in a clear and organized manner. Salient discussion points will be: 1. Process Examination 2. Material Selection 3. Steps For Successful Implementation 4. Possible Impediments 5. How to Avoid Risky Alternatives It will focus on procedures that will assist in the decision making process, and hopefully be of use in the choosing of environmentally sound equipment, chemicals, and methodologies.

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