The Experts below are selected from a list of 19245 Experts worldwide ranked by ideXlab platform
Udo Hartwig - One of the best experts on this subject based on the ideXlab platform.
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Full-Scale Model Tests On a Gravity Base Foundation For Offshore Wind Turbines
2011Co-Authors: Udo Hartwig, Thorsten Bierer, Jan SommerAbstract:During the last few years Ed. Zueblin AG has been designing a new type of Gravity Base foundation for multi-megawatt offshore wind turbines. As there is no proven experience available up to now, which allows the verification of calculation models for describing the mechanical behavior of cyclically loaded Gravity Base foundations, Zueblin decided to carry out full-scale model tests with their novel foundation type. The cyclic loading with more than 1 million load cycles is applied by hydraulic jacks and steel cables to the foundation, which is located inside a flooded construction pit close to the North Sea coast. For the measurements of pore pressures, total stresses and displacements in the subsoil, as well as of the foundation itself, approximately 150 measuring sensors in total have been installed. The tests focus on the possible accumulation of differential settlements and pore pressures in the subsoil due to the cyclic loading.
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cyclic response of granular subsoil under a Gravity Base foundation for offshore wind turbines
ASME 2011 30th International Conference on Ocean Offshore and Arctic Engineering, 2011Co-Authors: Stefanus Safinus, Germán Sedlacek, Udo HartwigAbstract:It is essential in the design of Gravity foundations under cyclic loading that inadmissibly large reductions of the subsoil bearing capacity due to the accumulated pore water pressure (loss of stability) and tilting of the foundation caused by the accumulation of settlements (loss of serviceability) are ruled out. This paper describes a procedure to predict these phenomena in non-cohesive subsoils. Real irregular loads during the service life of the structure can be idealized into parcels of uniform cyclic loads. Using the “High Cyclic Accumulation Model” proposed by Niemunis [1] the strain accumulation and thus the settlement of the subsoil due to the cyclic loads occurring within the service life of the wind turbine can be estimated. The pore pressure development is analyzed by dividing the mechanism in a pore pressure build-up phase in undrained condition (analytical calculation) and a dissipation phase (3D-FEM-Calculation).Copyright © 2011 by ASME
Germán Sedlacek - One of the best experts on this subject based on the ideXlab platform.
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Geotechnical Stability of Gravity Base Foundations for Offshore Wind Turbines on Granular Soils
Volume 4: Offshore Geotechnics; Ronald W. Yeung Honoring Symposium on Offshore and Ship Hydrodynamics, 2012Co-Authors: Germán Sedlacek, Alina Miehe, Ana Libreros, Yousef HeiderAbstract:Offshore wind energy farms have gained much attention during the last years in Germany and all over the world. In the construction of offshore wind turbines, piled foundations have been mostly used so far. However, Gravity Base foundations represent a good alternative as they minimize the typical high risks of the offshore works, such as weather-dependent installation, operational safety, construction sequence and performance. The whole wind energy turbine is assembled onshore and promptly transported to the planned location.In the design of the Gravity foundation under cyclic loading conditions, it is essential to avoid inadmissibly large reductions of the subsoil bearing capacity due to the excess pore-water pressure (loss of stability) and tilting of the foundation caused by the accumulation of settlements (loss of serviceability).This paper provides a description of the soil-mechanical behaviour of Gravity Base foundations and gives an account of the current available rules and standards for dimensioning foundations of this type. In this regard, a procedure for the geotechnical design of a Gravity Base foundation is laid out, where this work points out that the existing standards for designing Gravity Base foundations need to be further developed. Moreover, a brief summary of the results at a full-scale model test, according to the present state of testing and knowledge, are given.Copyright © 2012 by ASME
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cyclic response of granular subsoil under a Gravity Base foundation for offshore wind turbines
ASME 2011 30th International Conference on Ocean Offshore and Arctic Engineering, 2011Co-Authors: Stefanus Safinus, Germán Sedlacek, Udo HartwigAbstract:It is essential in the design of Gravity foundations under cyclic loading that inadmissibly large reductions of the subsoil bearing capacity due to the accumulated pore water pressure (loss of stability) and tilting of the foundation caused by the accumulation of settlements (loss of serviceability) are ruled out. This paper describes a procedure to predict these phenomena in non-cohesive subsoils. Real irregular loads during the service life of the structure can be idealized into parcels of uniform cyclic loads. Using the “High Cyclic Accumulation Model” proposed by Niemunis [1] the strain accumulation and thus the settlement of the subsoil due to the cyclic loads occurring within the service life of the wind turbine can be estimated. The pore pressure development is analyzed by dividing the mechanism in a pore pressure build-up phase in undrained condition (analytical calculation) and a dissipation phase (3D-FEM-Calculation).Copyright © 2011 by ASME
L. Völgyesi - One of the best experts on this subject based on the ideXlab platform.
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Hungary’s New Gravity Base Network (MGH-2000) and It’s Connection to the European Unified Gravity Net
International Association of Geodesy Symposia, 2002Co-Authors: G. Csapó, L. VölgyesiAbstract:The modernization of the Hungarian Gravity Base Network was carried out in the framework of the establishment of the unified Gravity network of the Central-European countries. The objective of former networks and the necessity of development are reviewed. The scale of the new network is guaranteed in SI system by the numerous absolute Gravity measurements carried out of late years. The applied observation methods, data processing and adjustment procedures are presented. The results of the comparison of Unified European Gravity Network’94 (UEGN-94), Czech, Slovakian and Austrian networks with the Hungarian network (MGH-2000) are discussed.
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hungary s new Gravity Base network mgh 2000 and it s connection to the european unified Gravity net
2002Co-Authors: G. Csapó, L. VölgyesiAbstract:The modernization of the Hungarian Gravity Base Network was carried out in the framework of the establishment of the unified Gravity network of the Central-European countries. The objective of former networks and the necessity of development are reviewed. The scale of the new network is guaranteed in SI system by the numerous absolute Gravity measurements carried out of late years. The applied observation methods, data processing and adjustment procedures are presented. The results of the comparison of Unified European Gravity Network’94 (UEGN-94), Czech, Slovakian and Austrian networks with the Hungarian network (MGH-2000) are discussed.
Stefanus Safinus - One of the best experts on this subject based on the ideXlab platform.
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cyclic response of granular subsoil under a Gravity Base foundation for offshore wind turbines
ASME 2011 30th International Conference on Ocean Offshore and Arctic Engineering, 2011Co-Authors: Stefanus Safinus, Germán Sedlacek, Udo HartwigAbstract:It is essential in the design of Gravity foundations under cyclic loading that inadmissibly large reductions of the subsoil bearing capacity due to the accumulated pore water pressure (loss of stability) and tilting of the foundation caused by the accumulation of settlements (loss of serviceability) are ruled out. This paper describes a procedure to predict these phenomena in non-cohesive subsoils. Real irregular loads during the service life of the structure can be idealized into parcels of uniform cyclic loads. Using the “High Cyclic Accumulation Model” proposed by Niemunis [1] the strain accumulation and thus the settlement of the subsoil due to the cyclic loads occurring within the service life of the wind turbine can be estimated. The pore pressure development is analyzed by dividing the mechanism in a pore pressure build-up phase in undrained condition (analytical calculation) and a dissipation phase (3D-FEM-Calculation).Copyright © 2011 by ASME
G. Csapó - One of the best experts on this subject based on the ideXlab platform.
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Hungary’s New Gravity Base Network (MGH-2000) and It’s Connection to the European Unified Gravity Net
International Association of Geodesy Symposia, 2002Co-Authors: G. Csapó, L. VölgyesiAbstract:The modernization of the Hungarian Gravity Base Network was carried out in the framework of the establishment of the unified Gravity network of the Central-European countries. The objective of former networks and the necessity of development are reviewed. The scale of the new network is guaranteed in SI system by the numerous absolute Gravity measurements carried out of late years. The applied observation methods, data processing and adjustment procedures are presented. The results of the comparison of Unified European Gravity Network’94 (UEGN-94), Czech, Slovakian and Austrian networks with the Hungarian network (MGH-2000) are discussed.
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hungary s new Gravity Base network mgh 2000 and it s connection to the european unified Gravity net
2002Co-Authors: G. Csapó, L. VölgyesiAbstract:The modernization of the Hungarian Gravity Base Network was carried out in the framework of the establishment of the unified Gravity network of the Central-European countries. The objective of former networks and the necessity of development are reviewed. The scale of the new network is guaranteed in SI system by the numerous absolute Gravity measurements carried out of late years. The applied observation methods, data processing and adjustment procedures are presented. The results of the comparison of Unified European Gravity Network’94 (UEGN-94), Czech, Slovakian and Austrian networks with the Hungarian network (MGH-2000) are discussed.
