TY - CONF A1 - Balscheit, Hagen A1 - Victor, A. A1 - Thiele, Marc A1 - Cuéllar, Pablo A1 - Baeßler, Matthias A1 - Lüddecke, F. T1 - Experimental Investigation on Buckling Behavior of soil-embedded Piles N2 - Monopiles are currently the predominant foundation type for offshore wind turbines in Europe. Due to the increasing dimensions of the turbines, pile diameters beyond 10m become necessary. A design-relevant failure mode of monopiles is the local buckling of the pile wall in the embedded sections. Relevant buckling guidelines do not consider the soil-structure interaction specifically, although the embedment may allow for a reduction of wall thickness. However, Eurocode-based design concepts require a validation with comparative buckling cases for validation, either in terms of buckling curve parameters for both the algebraic stress-based and semi-numerical LBA/MNA design concept or as a calibration factor kGMNIA for fully numerical GMNIA calculations. These parameters are not yet available for embedded shells. To close this gap, we have conducted experiments on piles embedded in sand to investigate local buckling under soil-structure-interaction. The results will be used to calibrate numerical models. This research was carried out as part of the VERBATIM research project, funded by PTJ/BMWK and supported by the Carbon Trust's Offshore Wind Accelerator consortium. T2 - EUROSTEEL 2023 CY - Amsterdam, The Netherlands DA - 11.09.2023 KW - Wind KW - Wind Energy KW - Shell Buckling KW - Offshore KW - Soil-Structure-Interaction PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583641 DO - https://doi.org/10.1002/cepa.2313 SN - 2509-7075 VL - 6 IS - 3-4 SP - 1729 EP - 1734 PB - Ernst & Sohn Gmb AN - OPUS4-58364 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zinas, Orestis A1 - Papaioannou, Iason A1 - Schneider, Ronald A1 - Cuéllar, Pablo A1 - Baeßler, Matthias T1 - 3D spatial modelling of CPT data for probabilistic preliminary assessment of potential pile tip damage upon collision with boulders N2 - Tip damage of monopiles from boulder collisions during installation has emerged as a critical design issue, primarily due to the combination of the widespread use of large-diameter piles and the complexity of the ground conditions at the available sites. Recently, a framework relating potential pile tip damage to cone tip resistance from Cone Penetration Tests (CPTs) has been proposed in the literature. Gaussian processes are powerful stochastic models that enable probabilistic spatial interpolation of soil data at any location within a site. On this basis, this study utilizes sparse CPT data from a site in the North Sea, to first develop an efficient Gaussian process regression model, which is used to derive a three-dimensional (3D) probabilistic predictive map of the cone tip resistance. Assuming deterministic loading conditions and a factual collision with a boulder of pre-defined properties, the cone tip resistance predictive model is subsequently used for a probabilistic preliminary assessment of potential pile tip damage. Results of the analysis are realistic 3D probability maps of potential damage that aim to support engineering judgment and contribute towards cost-effective site investigation planning and offshore wind farm design. T2 - 5th International Symposium on Frontiers in Offshore Geotechnics (ISFOG 2025) CY - Nantes, France DA - 09.06.2025 KW - CPT data KW - Gaussian process regression KW - Boulder impact KW - Preliminary pile tip damage assessment PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634417 SN - 978-2-85782-758-0 DO - https://doi.org/10.53243/ISFOG2025-323 SP - 505 EP - 510 PB - International Society for Soil Mechanics and Geotechnical Engineering CY - London AN - OPUS4-63441 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baeßler, Matthias A1 - Balscheit, Hagen A1 - Geißler, Peter A1 - Schepers, Winfried A1 - Cuèllar, Pablo T1 - Evaluation of pile tip buckling based on large scale tests N2 - Der Beitrag beschreibt eine groß angelegte Versuchskampagne mit Pfahlrammungen, um das Risiko des plastischen Versagens der Pfahlspitze besser zu verstehen und numerische Modelle zu validieren. Ein numerisches Modell mit transientem Bodenkontakt zeigt eine gute Übereinstimmung mit den Testergebnissen. Parametervariationen verdeutlichen, wie empfindlich die Pfahlreaktion auf Imperfektionen und Randbedingungen ist. T2 - 5TH INTERNATIONAL SYMPOSIUM ON FRONTIERS IN OFFSHORE GEOTECHNICS CY - Nantes, France DA - 09.06.2025 KW - Pile Tip Buckling KW - Monopile KW - Offshore Windenergy KW - Driving Refusal KW - Large Scale Test PY - 2025 SN - 978-2-85782-758-0 DO - https://doi.org/10.53243/ISFOG2025-476 SP - 1218 EP - 1223 PB - International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE) CY - Nantes AN - OPUS4-63387 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kullolli, Borana A1 - Stutz, H. H. A1 - Cuéllar, Pablo A1 - Baeßler, Matthias A1 - Rackwitz, F. ED - Cardoso, A. S. ED - Borges, J. L. ED - Costa, P. A. ED - Gomes, A. T. ED - Marques, J. C. ED - Vieira, C. S. T1 - A generalized plasticity model adapted for shearing interface problems N2 - The response of many geotechnical systems, whose structural behavior depends on shearing effect, is closely related to soil structure interaction phenomenon. Experimentally it is found that the localisation of these effect happens at a narrow soil layer next to the structure. Numerically, this behavior can be modelled through inter-face elements and adequate constitutive models. In this work, a constitutive model in the framework of Gen-eralized Plasticity for sandy soils has been chosen to be adapted for the interface zone. From the direct shear experiments a sandy soil at loose and dense states under different normal pressures is considered. The adapted constitutive model is able to reproduce contraction and dilatation of the soil according to its relative density and it shows a good agreement with the experimental data. T2 - Conference CY - Porto, Portugal DA - 25.06.2018 KW - Numerical modelling KW - Soil-pile interaction KW - Interface KW - Shearing PY - 2018 SN - 978-1-138-33198-3 VL - 1 SP - 97 EP - 102 PB - NUMGE CY - Porto, Portugal AN - OPUS4-45721 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cuéllar, Pablo A1 - Baeßler, Matthias A1 - Rücker, Werner T1 - Relevant factors for the liquefaction susceptibility of cyclically loaded offshore monopiles in sand N2 - The offshore foundations may exhibit a relatively high liquefaction susceptibility due to the full saturation of the porous seabed and the cyclic nature of the typical offshore loads. Here, the particular relevance of some of the main factors that affect the liquefaction susceptibility of an offshore monopile will be addressed, focusing on the possibility of a progressive accumulation of residual pore water pressure within the saturated soil around a monopile under cyclic lateral loading. The discussion is based on numerical results obtained with a coupled FE model of the offshore foundation which includes the Biot-Zienkiewicz u-p model. A constitutive model of the Generalized Plasticity type has been used for the soil in order to reproduce important features of its behaviour under cyclic loading. This paper presents the findings derived from a parametric study of the problem and shows that the accumulation of residual pore pressure can produce significant changes of the pile's behaviour under external loading. The paper also investigates the effects caused by the loading from a realistic storm of moderate magnitude and the consequential transient degradation of the foundation's stiffness. T2 - Poromechanics V - 5th Biot conference on poromechanics CY - Vienna, Austria DA - 10.07.2013 KW - Soil liquefaction KW - Cyclic loads KW - Piles KW - Sand (hydraulic) KW - Offshore structures PY - 2013 SN - 978-0-7844-1299-2 DO - https://doi.org/10.1061/9780784412992.160 SP - 1336 EP - 1345 AN - OPUS4-28873 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bronsert, Jeffrey A1 - Baeßler, Matthias A1 - Cuéllar, Pablo A1 - Rücker, Werner ED - Dimitrovová, Z. ED - de Almeida, J.R. ED - Goncalves, R. T1 - Numerical modeling of train-track-interaction at bridge transition zones considering the long-term behaviour N2 - A train passage will induce elastic and plastic deformations in the ballast and ist underlying soll. Considering the short term behaviour the elastic deformations will overweight the plastic and therefore these can be neglected. Regarding the long term behaviour the plastic deformations will accumulate due to repeating traffic loads and lead to settlement and Deterioration ofthe track structure. A smooth settlement along the track (small differential Settlement) is acceptable, whereas large differential settlement accelerates the process of deterioration and reduces the safety and serviceability ofthe track. Especially a bridge transition zone is prone to large differential settlements, where the track deteriorates in the backfilling area of bridge abutments mainly due to stiffness changes between embankment and bridge, repeating traffic loads and displacements of the superstructure Ends on bridges. A numerical model will be presented, with a particular focus on the long term behaviour of the track at bridge transition zones under repeating traffic loads. The ahn ofthe Simulation is not the computation of every train Crossing but the analysis of the long term behaviour of the bridge transition zone based on single train crossings. The analysis is performed in the time domain, whereas the bridge, the track and the backfilling area are modelled by means of the finite T2 - ICOVP-2013 - 11th International conference on vibration problems CY - Lisbon, Portugal DA - 09.09.2013 KW - Train-track-interaction KW - Transition zone KW - Track settlement PY - 2013 SN - 978-989-96264-4-7 SP - 1 EP - 10 AN - OPUS4-29591 LA - eng 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 - Chen, A. ED - Frangopol, D.M. ED - Ruan, X. T1 - Evaluating the degradation of ballasted track at bridges for high-speed railways N2 - The bridge design for railway bridges is far more dependent on the interaction with the traffic and the carriageway than for road bridges. This is especially true for the specific demands of the track in highspeed railways. Both maintenance and safety of the track have to be considered. The most relevant sections for the design criteria can be located at the bridge transition zones. Based on experimental investigations it is shown that bridge joint displacements, changes in stiffness and uplifting of the sleeper are causes for an increased degradation and loss in strength of the ballasted track. With respect to high speed vibrations of the bridge deck can have an even more decisive impact. Bridge deck vibrations can lead to destabilization of the bailast. In a numerical study the behavior of the track at the bridge is illustrated. T2 - IABMAS 2014 - 7th International conference of bridge maintenance, safety and management CY - Shanghai, China DA - 07.07.2014 KW - Train-track-bridge-interaction KW - Bridge transition zone KW - Assessment criteria KW - Vehicle model KW - Numerical model PY - 2014 SN - 978-1-138-00103-9 SN - 978-1-315-76069-8 SP - 1 EP - 8 PB - CRC Press AN - OPUS4-31142 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bronsert, Jeffrey A1 - Baeßler, Matthias A1 - Cuéllar, Pablo A1 - Rücker, Werner ED - Cunha, A. ED - Caetano, E. ED - Ribeiro, P. ED - Müller, G. T1 - Assessment and optimisation of bridge transition zones on the basis of a numerical model for train-track-bridge interaction N2 - The main degradation process at bridge transition zones due to traffic loads is the appearance of differential settlements. Abrupt stiffness changes, repeating traffic loads and relative displacements of the superstructure ends on bridges often aggravate this problem. In this contribution, a 3D finite element (FE) model extended with a boundary formulation in the frame of the scaled-boundary finite element method (SBFEM) for a transient analysis of train-track-bridge interaction is presented. This numerical model permits an assessment of bridge transition zone with respect to permanent deformations of the track. The main focus lies on the modeling strategies for the vehicle and their impact on suitable assessment criteria for bridge transition zones. For this purpose, two different modeling strategies for the vehicle, a moving load model and a multibody model, have been compared and discussed on the basis of the assessment criteria. The results indicate that the model of the vehicle has a minor effect for an assessment on the embankment, but that the assessment on the bridge may show significant differences depending on whether the inertial components of the vehicle (multibody model) are considered. T2 - EURODYN 2014 - 9th International conference on structural dynamics CY - Porto, Portugal DA - 30.06.2014 KW - Train-track-bridge-interaction KW - Bridge transition zone KW - Assessment criteria KW - Vehicle model KW - Numerical model PY - 2014 SN - 978-972-752-165-4 SN - 2311-9020 SP - 799 EP - 804 AN - OPUS4-31144 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geißler, Peter A1 - Cuéllar, Pablo A1 - Hüsken, Götz A1 - Kühne, Hans-Carsten A1 - Baeßler, Matthias T1 - Insights into compaction grouting for offshore pile foundations N2 - The authors are currently investigating the possibility to apply compaction grouting for offshore pile foundations (Jacket piles as well as monopiles) as a possible retrofitting technique for an optimised foundation concept. In this research project, we are developing a design approach aiming to predict the ideal amount and properties of a grout for a specific soil situation and desired improvement of pile bearing capacity after Installation and during service time. Both numerical and experimental tests have been carried out to investigate the injection process during which a highly viscous grout is injected into the soil under high pressure to displace and compact the surrounding soil without fracturing it. The implicit Material Point Method (MPM) based on a mixed formulation is the numerical technique chosen to deal with the expected large deformations and the arbitrary shape of the developing grout bulb. The usage of MPM prevents both the need of remeshing and the numerical instability induced by extensive mesh distortion. For validation with experimental results, we have constructed a testing chamber with one transparent sidewall. This chamber enables us to observe the injection process directly at the transparent vertical window and to measure the in-plane soil displacements and strains by means of the Digital Image Correlation (DIC) technique. The results already reveal the interrelation of soil and grout properties for a successful usage of this common ground improvement technique. T2 - 37th International Conference on Ocean, Offshore and Arctic Engineering (OMAE 2018) CY - Madrid, Spain DA - 18.06.2018 KW - Offshore pile foundation KW - Compaction grouting KW - Material Point Method (MPM) KW - Mixed formulation KW - Digital Image Correlation (DIC) PY - 2018 SN - 978-0-7918-5130-2 SN - 2153-4772 VL - 9 SP - V009T10A013, 1 EP - 9 AN - OPUS4-46004 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kemmler, Samuel A1 - Cuéllar, Pablo A1 - Rettinger, C. A1 - Köstler, H. T1 - A Fluid-Solid Coupled Micromechanical Simulation for the Analysis of Piping Erosion During the Seabed Installation of a Suction Bucket Foundation N2 - Suction buckets are a promising concept for the foundations of offshore wind turbines. During the installation process of a suction bucket, localized fluidization of the granular soil, so-called piping erosion, may lead to installation failure. A 3D fluid-solid coupled micromechanical simulation is presented to study the occurrence of piping. An Euler-Lagrangian coupling employs momentum exchange between the fluid phase and the geometrically resolved particles. We investigate the behavior of the soil for three cases with varying prescribed suction velocities. We observe piping in the case with the highest suction velocity by analyzing the deformation of the granular fabric and monitoring the differential pressure. The grains under the bucket wall-tip show the highest hydraulic gradients and forces at the onset of piping. This approach permits a detailed analysis of piping phenomena and brings novel insights on the triggering conditions for piping failure of suction-aided foundations. T2 - TC 105 International Symposium CY - Grenoble, France DA - 23.09.2024 KW - Micromechanical simulation KW - Piping erosion KW - Suction bucket foundation PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629461 DO - https://doi.org/10.1088/1755-1315/1480/1/012024 SN - 1755-1307 VL - 1480 IS - 1 SP - 1 EP - 4 PB - IOP Publishing AN - OPUS4-62946 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -