The Experts below are selected from a list of 189 Experts worldwide ranked by ideXlab platform
Hans F. Burcharth - One of the best experts on this subject based on the ideXlab platform.
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Stability of cube armoured roundheads exposed to long crested and short crested waves
Coastal Engineering, 2016Co-Authors: Enrique Maciñeira, Hans F. BurcharthAbstract:Abstract The paper presents an update of the stability formulae by Macineira and Burcharth (2007) for cube armoured roundheads exposed to long- and short-crested waves. Reanalysis of former model test results and supplementary new model tests leads to a more precise set of formulae covering long-crested and short-crested waves. The formulae are valid for two layers of randomly placed cubes, ranges of head diameter, slope, cube mass density and wave steepness.
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On front slope stability of berm breakwaters
Coastal Engineering, 2013Co-Authors: Hans F. BurcharthAbstract:Abstract The short communication presents application of the conventional Van der Meer stability formula for low-crested breakwaters for the prediction of front slope erosion of statically stable berm breakwaters with relatively high berms. The method is verified ( Burcharth, 2008 ) by comparison with the reshaping of a large Norwegian breakwater exposed to the North Sea waves. As a motivation for applying the Van der Meer formula a discussion of design parameters related to berm breakwater stability formulae is given. Comparisons of front erosion predicted by the use of the Van der Meer formula with model test results including tests presented in Sigurdarson and Van der Meer (2011) are discussed. A proposal is presented for performance of new model tests with the purpose of developing more accurate formulae for the prediction of front slope erosion as a function of front slope, relative berm height, relative berm width, method of armour stone placement, and hydraulic parameters. The formulae should cover the structure range from statically stable berm breakwaters to conventional double layer armoured breakwaters.
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STABILITY OF HARDLY RESHAPING BERM BREAKWATERS
Coastal Engineering Proceedings, 2012Co-Authors: Thomas Lykke Andersen, Hans F. Burcharth, Jentsje W. Van Der Meer, Sigurdur SigurdarsonAbstract:The present paper deals with stability of berm breakwaters designed to be hardly or sometimes partly reshaping. Burcharth (2008, 2011) showed by comparison to the performance of a prototype berm breakwater that the Van der Meer formulae for stability of conventional rock armour including low crests could predict the deformations of the front slope in terms of the eroded area. The present paper verifies the method by comparison to model test results. It is found that the Van der Meer formula for plunging waves predicts very well the eroded area of the reshaped profile, even if it is applied in the surging wave area. Moreover, a simple method to estimate the erosion area based on recession formulae and the depth of intersection of reshaped and initial profile is presented and is applicable for hardly reshaping to fully reshaping. Even when using the only very simple and inaccurate estimate of the depth of intersection the last method leads to scatter quite similar to the first method when considering hardly and partly reshaping berm breakwaters. The influence of the slope angle is though expected to be more correctly included for hardly reshaping breakwaters using the method for straight non-overtopped slopes when the slope angle is 1:1.5 or flatter.
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Estimation of Partial Safety Factors and Target Failure Probability Based on Cost Optimization of Rubble Mound Breakwaters
2010Co-Authors: Hans F. BurcharthAbstract:The breakwaters are designed by considering the cost optimization because a human risk is seldom considered. Most breakwaters, however, were constructed without considering the cost optimization. In this study, the optimum return period, target failure probability and the partial safety factors were evaluated by applying the cost optimization to the rubble mound breakwaters in Korea. The applied method was developed by Hans F. Burcharth and John D. Sorensen in relation to the PIANC Working Group 47. The optimum return period was determined as 50 years in many cases and was found as 100 years in the case of high real interest rate. Target failure probability was suggested by using the probabilities of failure corresponding to the optimum return period and those of reliability analysis of existing structures. The final target failure probability is about 60% for the initial limit state of the national design standard and then the overall safety factor is calculated as 1.09. It is required that the nominal diameter and weight of armor are respectively 9% and 30% larger than those of the existing design method. Moreover, partial safety factors considering the cost optimization were compared with those calculated by Level 2 analysis and a fairly good agreement was found between the two methods especially the failure probability less than 40%.
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optimum safety levels and design rules for the icelandic type berm breakwater
Proceedings of the 5th Coastal Structures International Conference CSt07, 2009Co-Authors: Sigurdur Sigurdarson, Hans F. Burcharth, Jentsje Van Der Meer, John Dalsgaard SorensenAbstract:acceptance number: 60. Paper title: OPTIMUM SAFETY LEVELS AND DESIGN RULES FOR THE ICELANDIC-TYPE BERM BREAKWATER Authors: Sigurdur Sigurdarson, Jentsje W. van der Meer, Hans F. Burcharth and John Dalsgaard Sorensen,
Burcharth, Hans F. - One of the best experts on this subject based on the ideXlab platform.
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Desk Study Tools for Upgrade of Breakwaters against Increased Loadings Caused by Climate Change
Bundesanstalt für Wasserbau, 2019Co-Authors: Eldrup, Mads Røge, Andersen, Thomas Lykke, Burcharth, Hans F.Abstract:Burcharth et al. (2014) studied different upgrade solutions for a typical shallow water revetment and found that the most economical solution was to add an extra layer of armour rocks tothe existing two layers. Because none of the existing design formulae for armour stability and overtopping cover designs with armour consisting of three layer of rocks, the related design parameters had to be estimated. R ecently performed physical model tests presented in Eldrup et al. (2019) provide information of the performance of three layer rock armour and formed the basis for determination of the related notional permeability factor in the Van der Meer (1988) rock armour stability formula. The application of this formula and the Eldrup and Lykke Andersen (2018) overtopping formula is discussed in relation to armour consisting of two and three layers of rocks. The study shows that upgrading from two to three rock armour is a method to increase the stability and reduce the wave overtopping of existing structures
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Stability of Hardly Reshaping Berm Breakwaters
'American Society of Civil Engineers (ASCE)', 2012Co-Authors: Andersen, Thomas Lykke, W. Van Der Meer, Jentsje, Burcharth, Hans F., Sigurdarson SigurdurAbstract:Stability of berm breakwaters has been dealt with by several authors like Van der Meer (1992) and Lykke Andersen & Burcharth (2010). The work of Van der Meer (1992) gives a very good estimate of the full reshaped profile for dynamically stable structures with a stability number Hs/ΔDn50 > 3 . However, berm breakwaters have in recent years mainly been designed as statically stable fully reshaping, or as partly and hardly reshaped breakwaters. Lykke Andersen and Burcharth (2010) and others have presented formulae to calculate the berm recession (Rec) which is an important damage parameter for reshaping berm breakwaters. The Lykke Andersen formula is a semi-empirical formula leading to a quite large application area regarding water depth and initial front slope compared to the other empirical formulae.Stability of berm breakwaters has been dealt with by several authors like Van der Meer (1992) and Lykke Andersen & Burcharth (2010). The work of Van der Meer (1992) gives a very good estimate of the full reshaped profile for dynamically stable structures with a stability number Hs/ΔDn50 > 3 . However, berm breakwaters have in recent years mainly been designed as statically stable fully reshaping, or as partly and hardly reshaped breakwaters. Lykke Andersen and Burcharth (2010) and others have presented formulae to calculate the berm recession (Rec) which is an important damage parameter for reshaping berm breakwaters. The Lykke Andersen formula is a semi-empirical formula leading to a quite large application area regarding water depth and initial front slope compared to the other empirical formulae
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3-D Hydraulic Model Testing of the New Roundhead in Suape, Brazil
Department of Civil Engineering Aalborg University, 2009Co-Authors: Andersen, Thomas Lykke, Burcharth, Hans F., Sipavicius A., Le Querré A.Abstract:This report deals with a three-dimensional model test study of the extension of the breakwater in Suape, Brazil. The roundhead was tested for stability in various sea conditions. The length scale used for the model tests was 1:35. Unless otherwise specified all values given in this report are prototype values obtained by Froude scaling.Ph.D. Thomas Lykke Andersen was in charge of the model tests and assisted by Aurimas Sipavicius and Alban Le Querré. Engineer assistant Niels Drustrup and Kurt S. Sørensen assisted in the laboratory with the building and instrumentation of the models. Professor, H. F. Burcharth assisted with the planning of the model testing, test observations and the reporting.This report deals with a three-dimensional model test study of the extension of the breakwater in Suape, Brazil. The roundhead was tested for stability in various sea conditions. The length scale used for the model tests was 1:35. Unless otherwise specified all values given in this report are prototype values obtained by Froude scaling.Ph.D. Thomas Lykke Andersen was in charge of the model tests and assisted by Aurimas Sipavicius and Alban Le Querré. Engineer assistant Niels Drustrup and Kurt S. Sørensen assisted in the laboratory with the building and instrumentation of the models. Professor, H. F. Burcharth assisted with the planning of the model testing, test observations and the reporting.
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2-D Model Test Study of the Suape Breakwater, Brazil
Department of Civil Engineering Aalborg University, 2009Co-Authors: Andersen, Thomas Lykke, Burcharth, Hans F., Sopavicius A., Le Querré A.Abstract:This report deals with a two-dimensional model test study of the extension of the breakwater in Suape, Brazil. One cross-section was tested for stability and overtopping in various sea conditions. The length scale used for the model tests was 1:35. Unless otherwise specified all values given in this report are prototype values by assuming Froude scaling.Ph.D. Thomas Lykke Andersen were in charge of the model tests and assisted by Aurimas Sipavicius and Alban Le Querré. Engineer assistant Niels Drustrup and Kurt S. Sørensen assisted in the laboratory with the building and instrumentation of the models. Professor, H. F. Burcharth assisted with the planning of the model testing, test observations and the reporting.
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On Optimum Safety Levels of Breakwaters
Curran Associates Inc., 2006Co-Authors: Burcharth, Hans F., Sørensen, John DalsgaardAbstract:The paper presents results from numerical simulations performed with the objective of identifying optimum design safety levels of conventional rubble mound and caisson breakwaters, corresponding to the lowest costs over the service life of the structures. The work is related to the PIANC Working Group 47 on "Selection of type of breakwater structures". The paper summaries results given in Burcharth and Sorensen (2005) related to outer rubble mound breakwaters but focus on optimum safety levels for outer caisson breakwaters on low and high rubble foundations placed on sea beds strong enough to resist geotechnical slip failures. Optimum safety levels formulated for use both in deterministic and probabilistic design procedures are given. Results obtained so far indicate that the optimum safety levels for caisson breakwaters are much higher than for rubble mound breakwaters.The paper presents results from numerical simulations performed with the objective of identifying optimum design safety levels of conventional rubble mound and caisson breakwaters, corresponding to the lowest costs over the service life of the structures. The work is related to the PIANC Working Group 47 on "Selection of type of breakwater structures". The paper summaries results given in Burcharth and Sorensen (2005) related to outer rubble mound breakwaters but focus on optimum safety levels for outer caisson breakwaters on low and high rubble foundations placed on sea beds strong enough to resist geotechnical slip failures. Optimum safety levels formulated for use both in deterministic and probabilistic design procedures are given. Results obtained so far indicate that the optimum safety levels for caisson breakwaters are much higher than for rubble mound breakwaters.
Jorgen Juhl - One of the best experts on this subject based on the ideXlab platform.
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Berm breakwater structures: Berm breakwater trunk exposed to oblique waves
1996Co-Authors: A Alikhani, R.g. Tomasicchio, Jorgen JuhlAbstract:The major part of the research on berm breakwaters has concentrated on the berm reshaping of a trunk section exposed to head-on waves. Recent research included aspects related to individual stone movements under perpendicular wave attack (eg Tomasicchio et al). For a berm breakwater trunk section consisting of berm stones smaller than a certain size, the stones will continue to move in the wave direction (longshore transport) when the breakwater is exposed to oblique waves. Only a little research has been made to study the effect of oblique waves on the reshaping and longshore transport of berm breakwaters (eg Burcharth and Frigaard, and Van der Meer and Veldman). A series of comprehensive model tests and subsequent analyses were carried out with the aim to study the influence of wave obliquity on the reshaping process, on the initiation of longshore transport, and on the longshore transport rate. The model set-up and test programme are described in Juhl et al.
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Berm breakwater structures: Roundhead stability of berm breakwaters
1996Co-Authors: Jorgen Juhl, Peter Sloth, A Alikhani, Renata ArchettiAbstract:For berm breakwaters as compared with traditional rubble mound breakwaters, special measures have to be taken for the breakwater roundhead. If stone displacements occur on a roundhead, the stones will be moved in the wave direction and will loose most of their stabilising effect. The major part of the research on berm breakwaters has concentrated on the reshaping of the seaward side of the trunk under perpendicular wave attack. Only a little research has been made to study the stability of berm breakwater roundheads (eg Burcharth and Frigaard, Jensen and Sorensen, and Van der Meer and Veldman). Comprehensive three-dimensional (3D) model tests were carried out to study the reshaping of the roundhead as function of the wave conditions (wave height and wave period) and the angle of wave incidence. The reshaping process and the movements of stones on the berm were analysed based on both profile measurements and observations.
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Berm breakwater structures: Roundhead stability of berm breakwaters / Reshaping breakwater - Longshore transport and recession of the berm
1995Co-Authors: Jorgen Juhl, Peter Sloth, A Alikhani, Renata ArchettiAbstract:For berm breakwaters as compared with traditional rubble mound breakwaters, special measures have to be taken for the breakwater roundhead. If stone displacements occur on a roundhead, the stones will be moved in the wave direction and will loose most of their stabilising effect. A point of special concern is whether, and under which conditions, a berm breakwater roundhead will develop in a way that in the long-term will lead to structural failure. The major part of the research on berm breakwaters has concentrated on the reshaping of the seaward side cif the trunk under perpendicular wave attack. Only a little research has been made to study the stability of berm breakwater roundheads (eg Burcharth and Frigaard, Jensen and Serensen, and Van der Meer and Veldman). Comprehensive three-dimensional model tests have been carried out to study the reshaping of the roundhead as function of the wave conditions (wave height and wave period) and the angle of wave incidence. The reshaping process and the movements of stones on the berm have been analysed based on both profile measurements and observations.
Juhl J. - One of the best experts on this subject based on the ideXlab platform.
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Berm breakwater structures: Roundhead stability of berm breakwaters
'Research Society of Buddhism and Cultural Heritage', 1996Co-Authors: Juhl J., Alikhani A., Sloth P., Archetti R.Abstract:For berm breakwaters as compared with traditional rubble mound breakwaters, special measures have to be taken for the breakwater roundhead. If stone displacements occur on a roundhead, the stones will be moved in the wave direction and will loose most of their stabilising effect. The major part of the research on berm breakwaters has concentrated on the reshaping of the seaward side of the trunk under perpendicular wave attack. Only a little research has been made to study the stability of berm breakwater roundheads (eg Burcharth and Frigaard, Jensen and Sorensen, and Van der Meer and Veldman). Comprehensive three-dimensional (3D) model tests were carried out to study the reshaping of the roundhead as function of the wave conditions (wave height and wave period) and the angle of wave incidence. The reshaping process and the movements of stones on the berm were analysed based on both profile measurements and observations.Berm Breakwater
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Berm breakwater structures: Berm breakwater trunk exposed to oblique waves
'Research Society of Buddhism and Cultural Heritage', 1996Co-Authors: Alikhani A., Tomasicchio R.g., Juhl J.Abstract:The major part of the research on berm breakwaters has concentrated on the berm reshaping of a trunk section exposed to head-on waves. Recent research included aspects related to individual stone movements under perpendicular wave attack (eg Tomasicchio et al). For a berm breakwater trunk section consisting of berm stones smaller than a certain size, the stones will continue to move in the wave direction (longshore transport) when the breakwater is exposed to oblique waves. Only a little research has been made to study the effect of oblique waves on the reshaping and longshore transport of berm breakwaters (eg Burcharth and Frigaard, and Van der Meer and Veldman). A series of comprehensive model tests and subsequent analyses were carried out with the aim to study the influence of wave obliquity on the reshaping process, on the initiation of longshore transport, and on the longshore transport rate. The model set-up and test programme are described in Juhl et al.Berm Breakwater
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Berm breakwater structures: Roundhead stability of berm breakwaters / Reshaping breakwater - Longshore transport and recession of the berm
Imperial College, 1995Co-Authors: Juhl J., Alikhani A., Sloth P., Archetti R.Abstract:For berm breakwaters as compared with traditional rubble mound breakwaters, special measures have to be taken for the breakwater roundhead. If stone displacements occur on a roundhead, the stones will be moved in the wave direction and will loose most of their stabilising effect. A point of special concern is whether, and under which conditions, a berm breakwater roundhead will develop in a way that in the long-term will lead to structural failure. The major part of the research on berm breakwaters has concentrated on the reshaping of the seaward side cif the trunk under perpendicular wave attack. Only a little research has been made to study the stability of berm breakwater roundheads (eg Burcharth and Frigaard, Jensen and Serensen, and Van der Meer and Veldman). Comprehensive three-dimensional model tests have been carried out to study the reshaping of the roundhead as function of the wave conditions (wave height and wave period) and the angle of wave incidence. The reshaping process and the movements of stones on the berm have been analysed based on both profile measurements and observations.Berm Breakwater
Alikhani A. - One of the best experts on this subject based on the ideXlab platform.
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Berm breakwater structures: Parametric study of reshaped profile under head-on and oblique waves
'Research Society of Buddhism and Cultural Heritage', 1996Co-Authors: Alikhani A., Frigaard P., Hald T.Abstract:In order to describe the reshaping breakwater profile, the profile has to be schematized into profile parameters. Static stability is describe by damage and reshaping breakwaters by the profile. The profile can be schematized by profile parameters such as height and length parameters. Burcharth, and Frigaard (1988) made the first systematic study of oblique wave attack the reshaping breakwaters. Burcharth, and Frigaard (1988) introduced the linear recession rate of roundheads as a function of number of waves or storm duration under given wave height and wave period. Van der Meer (1998) schematized the reshaping breakwater with height, length and angle parameters. Van der Meer recommended that the influence of angle of wave attack must be analyzed in more detail. Van Hijum and Pilarczyk (1982) proposed a reduction factor SQRT(cos Psi) for shingle beach profiles under oblique waves.Berm Breakwater
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Berm breakwater structures: Roundhead stability of berm breakwaters
'Research Society of Buddhism and Cultural Heritage', 1996Co-Authors: Juhl J., Alikhani A., Sloth P., Archetti R.Abstract:For berm breakwaters as compared with traditional rubble mound breakwaters, special measures have to be taken for the breakwater roundhead. If stone displacements occur on a roundhead, the stones will be moved in the wave direction and will loose most of their stabilising effect. The major part of the research on berm breakwaters has concentrated on the reshaping of the seaward side of the trunk under perpendicular wave attack. Only a little research has been made to study the stability of berm breakwater roundheads (eg Burcharth and Frigaard, Jensen and Sorensen, and Van der Meer and Veldman). Comprehensive three-dimensional (3D) model tests were carried out to study the reshaping of the roundhead as function of the wave conditions (wave height and wave period) and the angle of wave incidence. The reshaping process and the movements of stones on the berm were analysed based on both profile measurements and observations.Berm Breakwater
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Berm breakwater structures: Berm breakwater trunk exposed to oblique waves
'Research Society of Buddhism and Cultural Heritage', 1996Co-Authors: Alikhani A., Tomasicchio R.g., Juhl J.Abstract:The major part of the research on berm breakwaters has concentrated on the berm reshaping of a trunk section exposed to head-on waves. Recent research included aspects related to individual stone movements under perpendicular wave attack (eg Tomasicchio et al). For a berm breakwater trunk section consisting of berm stones smaller than a certain size, the stones will continue to move in the wave direction (longshore transport) when the breakwater is exposed to oblique waves. Only a little research has been made to study the effect of oblique waves on the reshaping and longshore transport of berm breakwaters (eg Burcharth and Frigaard, and Van der Meer and Veldman). A series of comprehensive model tests and subsequent analyses were carried out with the aim to study the influence of wave obliquity on the reshaping process, on the initiation of longshore transport, and on the longshore transport rate. The model set-up and test programme are described in Juhl et al.Berm Breakwater
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Berm breakwater structures: Roundhead stability of berm breakwaters / Reshaping breakwater - Longshore transport and recession of the berm
Imperial College, 1995Co-Authors: Juhl J., Alikhani A., Sloth P., Archetti R.Abstract:For berm breakwaters as compared with traditional rubble mound breakwaters, special measures have to be taken for the breakwater roundhead. If stone displacements occur on a roundhead, the stones will be moved in the wave direction and will loose most of their stabilising effect. A point of special concern is whether, and under which conditions, a berm breakwater roundhead will develop in a way that in the long-term will lead to structural failure. The major part of the research on berm breakwaters has concentrated on the reshaping of the seaward side cif the trunk under perpendicular wave attack. Only a little research has been made to study the stability of berm breakwater roundheads (eg Burcharth and Frigaard, Jensen and Serensen, and Van der Meer and Veldman). Comprehensive three-dimensional model tests have been carried out to study the reshaping of the roundhead as function of the wave conditions (wave height and wave period) and the angle of wave incidence. The reshaping process and the movements of stones on the berm have been analysed based on both profile measurements and observations.Berm Breakwater
