TY - CHAP A1 - Rücker, Werner A1 - Cuéllar, Pablo A1 - Georgi, Steven A1 - Karabeliov, Krassimire A1 - Baeßler, Matthias A1 - Johnsen, Björn ED - Durstewitz, M. ED - Lange, B. T1 - Please Avoid Tilting - Application-Oriented Design and Monitoring Model for Foundation Structures Subjected to Cyclic Loads N2 - A great deal is possible, even on the seabed. Together, wind and waves shake the foundations of the offshore wind turbines. "ere is also the “normal” current and ebb and #ow of the tides that are so distinctive in the North Sea. Pore water pressure can also occur on the seabed, loosening it. Where monopiles are involved, the worst case is that the stability of the whole turbine can be altered – even if such a monopile rammed into the seabed has a diameter of up to eight metres. Over half the planned offshore wind turbines in the North and Baltic Seas are to have monopile foundations, and over 40 % are to have multi-pile foundations, designed for example as a tripod. "is is why pile foundations and their loads deserve special attention. For one thing above all is to be avoided in plant operations, and that is the risk of turbine tilt. KW - Pile foundations KW - Offshore wind turbines KW - Cyclic loads PY - 2017 SN - 978-3-662-53178-5 DO - https://doi.org/10.1007/978-3-662-53179-2 SP - 53 EP - 59 PB - Springer AN - OPUS4-39340 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kullolli, Borana A1 - Cuéllar, Pablo A1 - Baeßler, Matthias T1 - On contact problem application for the local behavior of soil-pile interaction N2 - In this paper a shear test, which helps to study local behavior of the soil-pile interaction, is modelled numerically with the Finite Element Method as a 2D plane strain problem. A normal pressure on top and shear displacement on side were applied. So far, the material behavior was considered elastic for the sake of simplicity. The effect of thickness on contact elements and the presence of in plane stress has been highlighted. The purpose of the paper is to find a suitable contact element which represents more close to reality a soil-pile interaction problem under cyclic axial loading. Moreover, an insight on the presence of in-plane stress shows that it needs to be considered cautiously. T2 - ICCE2017 CY - Tirana, Albania DA - 12.10.2017 KW - Contact problem KW - Numerical modelling PY - 2017 SP - 167 EP - 174 PB - Polytechnic University of Tirana CY - Tirana, Albania AN - OPUS4-42962 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cuéllar, Pablo T1 - Deep foundations for offshore wind turbines. Lecture 1: Axial behaviour T1 - Cimentaciones profundas para aerogeneradores marinos - Parte 1: Comportamiento axial N2 - This presentation deals with the phenomenology and design of pile foundations for offshore wind turbines, and is divided into two lectures. The first lecture presents a brief introduction to the context and peculiarities of such foundations, and then focuses on the particular case of axially loaded piles. This part is most relevant for the relatively slender piles of the multi-pile substructures (i.e. jackets and tripods). A clear distinction between physical phenomenology and practical design is drawn here. T2 - Masters course on Soil Mechanics and Geotechnical Engineering. Geotechnical Laboratory of CEDEX CY - Online meeting DA - 21.04.2020 KW - Pile foundations KW - Offshore wind turbines KW - Physical phenomenology KW - Design methods PY - 2020 AN - OPUS4-51057 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cuéllar, Pablo T1 - Deep foundations for offshore wind turbines. Lecture 2: lateral behaviour and advanced topics T1 - Cimentaciones profundas para aerogeneradores marinos - Parte 2: Comportamiento lateral y tematica avanzada N2 - This presentation deals with the phenomenology and design of pile foundations for offshore wind turbines, and is divided into two lectures. The second lecture continues with the case of lateraly loaded offshore piles, which bears most relevance for the case of the monopile foundations. Here again, a clear separation between physical reality and design methods is intended. Finally, the last part of the second lecture introduces several advanced topics which lie outside the classical design approaches, namely the hydromechanical coupling effects (i.e. the excess pore-pressure generation around the monopiles), the cyclic pile fatigue and the so-called pile setup (i.e. the time effects on the axial pile capacity). The relevance of the latter two topics is illustrated with experimental results from a field testing campaign on real large-scale piles. T2 - Masters course on Soil Mechanics and Geotechnical Engineering. Geotechnical Laboratory of CEDEX CY - Online meeting DA - 21.04.2020 KW - Pile foundations KW - Offshore wind turbines KW - Physical phenomenology KW - Design methods PY - 2020 AN - OPUS4-51059 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cuéllar, Pablo T1 - State of the art and development perspectives of deep foundations for offshore wind converters T1 - Estado del arte y perspectivas de desarrollo de las cimentaciones profundas para aerogeneradores offshore N2 - This presentation provides an overview of the main geotechnical aspects associated with deep foundations in the context of offshore wind generation. The most common deep foundation typologies (large diameter monopiles and multipile typologies) as well as new trends under development (e.g. suction buckets) and their current limits will be briefly described. The talk concludes with a brief review of advanced topics not covered in classical pile design, such as hydromechanical coupling effects (pore pressure generation), cyclic accumulation of deformations, cyclic degradation of axial capacity or pile-setup gains. T2 - Ciclo de Conferencias: Aplicaciones de la Geotecnia en la generación de Energía. Sociedad Argentina de Ingeniería Geotécnica SAIG CY - Online meeting DA - 02.12.2020 KW - Offshore wind energy KW - Deep foundations KW - Offshore geomechanics PY - 2020 AN - OPUS4-51729 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cuéllar, Pablo T1 - An efficient GPU implementation of a micromechanical computational tool for erosion problems N2 - We present here a set of conceptual and numerical tools for a micromechanical simulation of general erosion problems involving fluid-saturated granular assemblies, whether frictional or cohesive. We propose a parallel computation using graphical processing units (GPUs) to treat large numbers of degrees of freedom with conventional desktop computers. The fluid phase is here simulated with a particle-resolved approach in the frame of the Lattice Boltzmann Method (LBM) while the granular solid phase is modelled as a collection of discrete particles from a Molecular Dynamics DEM perspective. The range of possible material behaviors for the solid granular phase is intended here to cover a broad spectrum from purely frictional to viscous cohesive materials with either brittle or transient debonding features. Specific details of the implementation and some validation cases will be put forward. To conclude we provide some exemplary applications in the field of soil erosion along with details on the parallel performance of the models. The results show that a micromechanical approach can be feasible and useful in practice, providing meaningful insights into complex phenomena like the erosion threshold and kinetics of weakly cemented soils. T2 - EWG-IE 2020 Workshop on "Innovative numerical methods for internal erosion processes" CY - Online meeting DA - 17.12.2020 KW - Erosion KW - Earthen hydraulic constructions KW - Micromechanical modelling KW - LBM-DEM coupling KW - GPU parallel computation PY - 2020 AN - OPUS4-51866 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baeßler, Matthias A1 - Rücker, Werner A1 - Cuéllar, Pablo A1 - Georgi, Steven A1 - Karabeliov, Krassimire T1 - Large-scale testing facility for cyclic axially loaded piles N2 - Offshore piles have to withstand predominantly cyclic axial loads when they are installed in multi-pile configurations, as in jacket foundations. The dimensions of the pile are governed by both the internal capacity and the fatigue behaviour of the steel cross-section as well as by its external capacity in the pile-soil interaction. Owing to the large numbers of piled foundations required for current and future offshore wind farms, there is an urgent need to optimize the dimensions and related costs of single piles. With regard to the pile capacity, two major topics of research are the determination of possible capacity gains due to pile ageing effects and proper consideration of cyclic degradation. In order to investigate both effects, a large-scale testing facility has been constructed at the BAM TTS site in Horstwalde near Berlin. This open-air facility allows large tubular driven piles to be loaded cyclically in both tension and compression while studying the ageing effects by introducing delays between the testing campaigns. First results already show a moderate increase in pile capacity over time. Concerning the anticipated capacity degradation of cyclically loaded piles, preliminary results show an unexpected behaviour. Additional tests are currently being conducted for further clarification. KW - Steel driven piles KW - Offshore foundations KW - Cyclic axial loading KW - Pile ageing KW - Large-scale field testing PY - 2013 DO - https://doi.org/10.1002/stco.201310028 SN - 1867-0520 SN - 1867-0539 VL - 6 IS - 3 SP - 200 EP - 206 PB - Ernst & Sohn CY - Berlin AN - OPUS4-29535 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cuéllar, Pablo T1 - Design challenges for Offshore wind-farms. From foundation mechanics to wind-farm aerodynamics N2 - This talk provides a brief introduction on general engineering design challenges for the offshore wind energy production. Some general features of the offshore wind-energy field from a civil engineering perspective are firstly presented, followed by a brief discussion of some of the main geomechanical issues for the foundation of the offshore turbines into the seabed. In the following part, an overview of relevant fluid-structure interactions and some options for an efficient numerical analysis are provided, where the hydromechanical Wave–Tower interaction is firstly discussed. Then, some general aspects of the windfarm aerodynamics are introduced. On the one hand, some modelling possibilities for the wake analysis of single turbines and turbine groups are discussed. And on the other hand the relevance of such analyses for a proper windfarm layout optimization is pointed out. In particular, this talk shows that: i) The bearing capacity of turbine multi-pile foundations can degrade under cyclic loading (waves, wind, …), while for monopile foundations cyclic hydromechanical coupling effects may take place, which may lead to a foundation softening; ii) Numerical analysis of a turbine’s interaction with wind/waves is useful and affordable, while simplified models can already provide a useful insight into the windfarm aerodynamics. iii) Turbulent wake analysis is very relevant for the windfarm layout. T2 - Colloquium "Energy systems compared", Winter semester 20/21, Faculty of Physics CY - Online meeting DA - 21.01.2021 KW - Offshore wind energy KW - Marine geotechnics KW - Fluid-structure interaction KW - Numerical modelling PY - 2021 AN - OPUS4-52038 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cuéllar, Pablo A1 - Baeßler, Matthias A1 - Georgi, Steven A1 - Rücker, Werner ED - Triantafyllidis, T. T1 - Special issues for the coupled transient simulation of laterally loaded offshore piles and novel experimental findings T2 - Workshop Gründung von Offshore-Windenergieanlagen CY - Karlsruhe, Germany KW - Offshore pile foundation KW - Cyclic lateral load KW - Pore pressure accumulation KW - Model testing PY - 2010 SN - 0453-3267 IS - 172 SP - 117 EP - 138 CY - Karlsruhe AN - OPUS4-24496 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cuéllar, Pablo T1 - Computational models and experimental testing of offshore foundations at BAM - Current works and open issues T2 - BAM-DTU Seminar on Design and maintenance of support structures for Offshore Wind Converters CY - Copenhagen, Denmark DA - 2011-10-25 PY - 2011 AN - OPUS4-24737 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cuéllar, Pablo T1 - Nuevos aspectos para el diseno estructural de generadores eólicos offshore en el Mar del Norte T2 - Workshop Fortnight of the Engineering (Quincena de la Ingenieria), Universidad de Cadiz UCA CY - Cadiz, Spain DA - 2012-03-20 PY - 2012 AN - OPUS4-25672 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baeßler, Matthias A1 - Bronsert, Jeffrey A1 - Cuéllar, Pablo A1 - Rücker, Werner ED - Pombo, J. T1 - The stability of ballasted tracks supported on vibrating bridge decks, abutments and transition zones N2 - The track on bridges is affected by cyclic and dynamic action arising from the train passage and the reaction of the track supporting structure. Concerning the track, the current bridge design procedures include two major engineering tasks: On the one hand the stability of the track supported on the bridge deck has to be satisfied. In order to reduce the deterioration of the track the elasticity of the track has to be adapted for the stiff bridge deck. Furthermore, lateral stability has also to be satisfied. The vibration of the bridge structure has to be taken into account because it can affect the stability of the ballasted track. On the other hand the transition zone between bridge structure, abutment and the track on the subgrade is a matter of permanent concern. The changes in stiffness, in the dynamic behavior arising from the rolling stock and the relative deflection between the bridge structure and the abutment induce a nearly unavoidable problem for the long term behaviour on the track. BAM has conducted intensive experimental work to study the behaviour of the ballasted track on dynamically excited bridges. The state of the art is a design value for the deck acceleration of 0.35 g as established in the ENV 1991-1. In our experimental investigations the design value was verified. The influence of a frequency content higher than 30 Hz and of single vibration amplitudes on the track deterioration was evaluated. Both vertical and lateral stability were investigated. The influence of vibrations on the lateral stability can be more severe since the lateral stability could involve a sudden failure of the track. Furthermore, a simulation tool was developed to calculate the lateral stability on a vibrating bridge deck. For this simulation tool a parameter study was undertaken [1] where combinations of the curvature of the bridge-track system, the design temperature and the bridge deck vibrations were investigated. Parts of this study are incorporated in this paper. In a current research project the investigations are extended to the interaction of the train-track-dynamics and the long term behaviour of the transition zone. The main emphasis is on the integration of the possible deterioration of the structural components in the numerical modelling of the relevant structural elements of the vehicle, the bridge and bridge abutment structure. An outlook is given to a complete model for the assessment of the track behaviour at railway bridges. T2 - 1st international conference on railway technology: research, development and maintenance CY - Las Palmas, Gran Canaria, Spain DA - 18.04.2012 KW - Ballast KW - Acceleration KW - Bridge deck KW - Track deterioration KW - Track stability KW - Transition zone PY - 2012 SN - 978-1-905088-53-9 DO - https://doi.org/10.4203/ccp.98.13 SN - 1759-3433 N1 - Serientitel: Civil-Comp Proceedings – Series title: Civil-Comp Proceedings VL - 98 IS - Paper 13 SP - 1 EP - 20 PB - Civil Comp Press AN - OPUS4-26900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Georgi, Steven A1 - Baeßler, Matthias A1 - Cuéllar, Pablo T1 - Verformungsakkumulation von Offshore-Pfahlgründungen unter zyklischer Belastung N2 - Die Berechnung von Verformungen lateral belasteter Pfahlgründungen bedingt in der Regel die Überführung der transienten Belastungen aus verschiedenen Umwelteinwirkungen in eine meist sinusförmige zyklische Belastung mit konstanter Amplitude. Dies bringt die Vernachlässigung der Reihenfolge, in der die realen Belastungen auftreten, mit sich. Die Voraussetzung dafür ist, dass der Einfluss dieser Reihenfolge auch tatsächlich gering ist. Da die meisten experimentellen Untersuchung hierzu sich auf die Elementebene und relativ geringe Zyklenzahlen beschränken, wird hier eine Versuchsserie präsentiert, in welcher Modellpfähle durch Zyklenpakete mit unterschiedlichen Amplituden in variierender Reihenfolge und hohen Lastspielzahlen belastet werden. Es zeigt sich ein geringer bis vernachlässigbarer Einfluss der Reihenfolge der Lastblöcke für reine Schwellbelastungen. T2 - 32. Baugrundtagung CY - Mainz, Germany DA - 2012-09-26 PY - 2012 SN - 9783981395358 SP - 97 EP - 104 CY - Essen AN - OPUS4-26769 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cuéllar, Pablo A1 - Baeßler, Matthias A1 - Rücker, Werner T1 - Pore-pressure accumulation and soil softening around pile foundations for offshore wind turbines T2 - OMAE 2012 - 31st International conference on ocean, offshore and artic engineering CY - Rio de Janeiro, Brazil DA - 2012-07-01 KW - Offshore pile foundation KW - Cyclic loading KW - Coupled numerical modelling KW - Pore-pressure accumulation KW - Softening KW - Liquefaction PY - 2012 SN - 978-0-7918-4491-5 VL - 4 SP - 219 EP - 228 PB - ASME CY - New York, N.Y. AN - OPUS4-26738 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -