The Experts below are selected from a list of 1278 Experts worldwide ranked by ideXlab platform
Hofland B. - One of the best experts on this subject based on the ideXlab platform.
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Influence of toe berm geometry on stability of reshaping berm breakwaters
'Elsevier BV', 2020Co-Authors: Shafieefar Mehdi, Shekari, Mohammad Reza, Hofland B.Abstract:Reshaping berm breakwaters have been mainly designed and built for water depth less than 20 m. In such Conditions, a toe structure may be needed to reduce bottom settlements and increase geotechnical stability in the loose Subsoil Condition. Also, a toe berm can be deployed to reduce the berm recession and increase the stability of the Reshaping berm breakwater, especially in deep water. Although many studies have been conducted to study the effects of toe berms on stability of conventional breakwaters, investigations on the influence of a toe berm on stability of reshaping berm breakwaters are rare. This paper presents results of an experimental work that has been carried out to investigate the influence of a toe berm on the hydraulic stability of reshaping berm breakwaters. In a 2D physical test setup in a wave flume, a total of 207 tests were conducted to systematically examine the effects of toe berm configuration on the reshaping of berm breakwaters with three types of armor stones. The experimental program covers the influence of different geometrical parameters of the toe berm on the berm recession under various sea state Conditions. Comparing results of berm recession of the cases having a toe structure with the cases without a toe berm shows that the amount of berm recession with toe berm is considerably less than the analogous amount for without toe structure. It is observed that an increasing toe berm width and thickness both have considerable influence on recession reduction. However, the toe depth has a relatively larger influence on recession than the toe width, and the influence is larger for higher stability numbers. It is concluded that a toe berm in front of reshaping berm breakwater not only does have influence on recession due to the depth influence and the changing wave Conditions, but also the toe depth has a direct influence on the reshaped profile by preventing the displaced rocks to fall down to deeper parts. Using the test results, a new formula is developed for estimation of berm recession by taking into account the influence of the toe berm configuration. Given an acceptable stability number (Ho) as a design criterion for reshaping berm breakwaters, the present method predicts that the recession can be reduced up to 35% by the application of a toe berm. Thus, the main berm width can be shortened, resulting in reduction of the required armor stones volume. So, by using a smaller stone size for the toe berm, the stability of the structure is secured and also the total cost of the breakwater can be reduced.Hydraulic Structures and Flood Ris
Keunbo Park - One of the best experts on this subject based on the ideXlab platform.
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a study on the dynamic lateral displacements of caisson quay walls in moderate earthquake regions
Journal of the Korean Geotechnical Society, 2008Co-Authors: Keunbo ParkAbstract:In this study, 28 earthquake records with magnitudes from 5.3 to 7.9 are selected for dynamic analysis in order to assess applicability of the earthquakes for domestic seismic design. The assessment is performed using the seismic spectrum analysis of energy and acceleration. Based on results of the analysis, four acceleration time histories, which satisfy the Korean design standard response spectrum, are proposed. From the dynamic analysis using earthquake magnitudes from 6.4 to 7.9, it is found that horizontal displacements corresponding to earthquake magnitudes greater than 7 are two times larger than those with magnitude 6.5. Therefore, it can be stated that use of strong earthquakes, such as Miyagiken-ken-oki earthquake (Ofunato, ) and Tokachi-oki earthquake (Hachinohe, ), for the seismic design in Korea is not applicable, and may prove to be excessively conservative due to overestimated seismic force. From the dynamic analyses using the proposed acceleration time histories, effects of caisson quay wall dimension and the Subsoil Condition are investigated as well. The simplified design charts to evaluate horizontal displacements of caisson quay wall are also proposed based on earthquake magnitude 6.5 that is appropriate in Korea.
Holmwood, Andrew Graham - One of the best experts on this subject based on the ideXlab platform.
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A numerical study of the suitability of rigid inclusion ground reinforcement beneath caisson quay walls
Department of Civil Engineering, 2017Co-Authors: Holmwood, Andrew GrahamAbstract:The objective of this study was to determine whether rigid inclusions are suitable for reinforcement of the foundation of a caisson quay wall functioning as a container terminal. Apart from their brittle behaviour under lateral loading, rigid inclusions are well suited to the large uniform loads and stringent post-construction deflection tolerances associated with container terminal structures. Their inherent strength and stiffness means they have certain advantages over other stiffening columns commonly used for ground reinforcement in port expansion projects. Their mechanical properties allow construction to unrestricted heights at any construction rate and, in theory, RIs can be applied to all soil types. Additionally the locations of many ports coincide with rivers, deltas and estuaries which are associated with poor soil Conditions often requiring ground improvement. Their suitability is of practical significance to port planners and engineers who are faced with the challenge of providing satisfactory foundation performance that is cost effective. The addition of RI ground reinforcement for this structural application would allow for greater flexibility in meeting these challenges. The literature review for this study was broad in its scope with emphasis placed on describing the mechanics of the problem, analysis methods and suitable installation methods for execution in the marine environment. One of the key outcomes of the literature review was identifying the problem of lateral loading due to "free-field" lateral ground movements. In light of this, suitable strategies for limiting and accommodating lateral loading of the RIs were proposed. A numerical study of the proposed ground improvement scheme was undertaken using the 3D finite element method. The key model outputs were caisson deflections and RI forces, moments and stresses, for the various simulated construction phases up to operational Conditions. The model results were assessed in terms of the key foundation performance criteria which were related to STS crane rail tolerances and limiting tensile stresses in the RIs. This study found that for a firm clay Subsoil Condition the proposed RI ground reinforcement scheme met the foundation performance criteria for this structural application provided (i) strategies to limit lateral loading were implemented and (ii) the RIs were reinforced over the length where they were not fully compressed. While this study provided insights into the behaviour of RIs for this structural application, ultimately suitability is a function of range of factors, in addition to the limited technical performance criteria derived for this study
Shafieefar Mehdi - One of the best experts on this subject based on the ideXlab platform.
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Influence of toe berm geometry on stability of reshaping berm breakwaters
'Elsevier BV', 2020Co-Authors: Shafieefar Mehdi, Shekari, Mohammad Reza, Hofland B.Abstract:Reshaping berm breakwaters have been mainly designed and built for water depth less than 20 m. In such Conditions, a toe structure may be needed to reduce bottom settlements and increase geotechnical stability in the loose Subsoil Condition. Also, a toe berm can be deployed to reduce the berm recession and increase the stability of the Reshaping berm breakwater, especially in deep water. Although many studies have been conducted to study the effects of toe berms on stability of conventional breakwaters, investigations on the influence of a toe berm on stability of reshaping berm breakwaters are rare. This paper presents results of an experimental work that has been carried out to investigate the influence of a toe berm on the hydraulic stability of reshaping berm breakwaters. In a 2D physical test setup in a wave flume, a total of 207 tests were conducted to systematically examine the effects of toe berm configuration on the reshaping of berm breakwaters with three types of armor stones. The experimental program covers the influence of different geometrical parameters of the toe berm on the berm recession under various sea state Conditions. Comparing results of berm recession of the cases having a toe structure with the cases without a toe berm shows that the amount of berm recession with toe berm is considerably less than the analogous amount for without toe structure. It is observed that an increasing toe berm width and thickness both have considerable influence on recession reduction. However, the toe depth has a relatively larger influence on recession than the toe width, and the influence is larger for higher stability numbers. It is concluded that a toe berm in front of reshaping berm breakwater not only does have influence on recession due to the depth influence and the changing wave Conditions, but also the toe depth has a direct influence on the reshaped profile by preventing the displaced rocks to fall down to deeper parts. Using the test results, a new formula is developed for estimation of berm recession by taking into account the influence of the toe berm configuration. Given an acceptable stability number (Ho) as a design criterion for reshaping berm breakwaters, the present method predicts that the recession can be reduced up to 35% by the application of a toe berm. Thus, the main berm width can be shortened, resulting in reduction of the required armor stones volume. So, by using a smaller stone size for the toe berm, the stability of the structure is secured and also the total cost of the breakwater can be reduced.Hydraulic Structures and Flood Ris
Shekari, Mohammad Reza - One of the best experts on this subject based on the ideXlab platform.
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Influence of toe berm geometry on stability of reshaping berm breakwaters
'Elsevier BV', 2020Co-Authors: Shafieefar Mehdi, Shekari, Mohammad Reza, Hofland B.Abstract:Reshaping berm breakwaters have been mainly designed and built for water depth less than 20 m. In such Conditions, a toe structure may be needed to reduce bottom settlements and increase geotechnical stability in the loose Subsoil Condition. Also, a toe berm can be deployed to reduce the berm recession and increase the stability of the Reshaping berm breakwater, especially in deep water. Although many studies have been conducted to study the effects of toe berms on stability of conventional breakwaters, investigations on the influence of a toe berm on stability of reshaping berm breakwaters are rare. This paper presents results of an experimental work that has been carried out to investigate the influence of a toe berm on the hydraulic stability of reshaping berm breakwaters. In a 2D physical test setup in a wave flume, a total of 207 tests were conducted to systematically examine the effects of toe berm configuration on the reshaping of berm breakwaters with three types of armor stones. The experimental program covers the influence of different geometrical parameters of the toe berm on the berm recession under various sea state Conditions. Comparing results of berm recession of the cases having a toe structure with the cases without a toe berm shows that the amount of berm recession with toe berm is considerably less than the analogous amount for without toe structure. It is observed that an increasing toe berm width and thickness both have considerable influence on recession reduction. However, the toe depth has a relatively larger influence on recession than the toe width, and the influence is larger for higher stability numbers. It is concluded that a toe berm in front of reshaping berm breakwater not only does have influence on recession due to the depth influence and the changing wave Conditions, but also the toe depth has a direct influence on the reshaped profile by preventing the displaced rocks to fall down to deeper parts. Using the test results, a new formula is developed for estimation of berm recession by taking into account the influence of the toe berm configuration. Given an acceptable stability number (Ho) as a design criterion for reshaping berm breakwaters, the present method predicts that the recession can be reduced up to 35% by the application of a toe berm. Thus, the main berm width can be shortened, resulting in reduction of the required armor stones volume. So, by using a smaller stone size for the toe berm, the stability of the structure is secured and also the total cost of the breakwater can be reduced.Hydraulic Structures and Flood Ris
