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 - Georgi, Steven A1 - Baeßler, Matthias A1 - Cuéllar, Pablo A1 - Karabeliov, Krassimire A1 - Rücker, Werner ED - Lutz, B. ED - Möller, G. ED - Rücker, Werner ED - Schiefelbein, N. T1 - Ermittlung von Beanspruchung und Verformungen von Pfahlgründungen - Messverfahren und Applikation N2 - Vor dem Hintergrund einer angestrebten größeren Unabhängigkeit der Energieversorgung von fossilen Energieträgern hat die Windenergie in den letzten Dekaden zunehmend an Bedeutung gewonnen. Dabei wird insbesondere die Energiegewinnung offshore in der Deutschen Nordsee, auf Grund dort vorhandener stetiger Winde und sinkender Akzeptanz von Windkraftanlagen an Land, forciert. Im Hinblick auf die Gründung dieser Anlagen wird technisches Neuland betreten. Angesichts von Wassertiefen bis über 25 m erhalten aufgelöste Gründungsstrukturen wie Tripod und Jacket oft den Vorzug vor Monopiles. Letztere waren wegen der geringen Produktions- und Installationskosten, der bisher am häufigsten angewandte Gründungstyp in flacheren Gewässern. Monopile- und Mehrpfahlgründung unterscheiden sich wesentlich im Abtrag der Belastung durch Beanspruchungen aus Wind und Wellen in den umgebenden Baugrund. Während beim Monopile die zyklischen Momente über laterale Bettung abgetragen werden, entstehen an den Mehrpfahlgründungen axiale Zug- und Druckbelastungspaare in gegenüberliegenden Pfählen. Die zyklischen Belastungen von Monopiles sind demnach hauptsächlich in lateraler Richtung zu erwarten, während für Mehrpfahlgründungen die zyklische Belastung einen überwiegend axialen Charakter aufweist. Die zyklischen axialen Lasten in den Pfählen der Mehrpfahlgründungen können die axialen Tragfähigkeiten insbesondere am Pfahlmantel reduzieren und damit evtl, zu einem Versagen der Gründung führen. T2 - Messen im Bauwesen 2014 - Neue Messtechnik und Anwendungsfälle CY - Berlin, Germany DA - 04.03.2014 KW - Zyklik KW - Pfahl KW - Tragfähigkeit KW - Dehnungsmessung PY - 2014 SN - 978-3-9815944-7-8 SP - 97 EP - 108 AN - OPUS4-30486 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zinas, Orestis A1 - Papaioannou, Iason A1 - Schneider, Ronald A1 - Cuéllar, Pablo T1 - Multivariate Gaussian Process for 3D subsurface stratigraphy prediction from CPT and labelled borehole data N2 - Quantifying uncertainties in subsurface properties and stratigraphy can lead to better understanding of the ground conditions and enhance the design and assessment of geotechnical structures. Several studies have utilized Cone Penetration Test (CPT) data and employed Bayesian and Machine Learning methods to quantify the geological uncertainty, based on the Robertson’s soil classification charts and the Soil Behaviour Type Index (Ic). The incorporation of borehole data can reduce the stratigraphic uncertainty. Significant challenges can arise, however, mainly due to the intrinsic differences between field and laboratory-based soil classification systems, which can potentially lead to inconsistent soil classification. To this end, this study proposes a multivariate Gaussian Process model that utilizes site-specific data and: i) jointly models multiple categorical (USCS labels) and continuous (Ic) variables, ii) learns a (shared) spatial correlation structure and the betweenoutputs covariance, and iii) produces two types of dependent classification outputs. The results indicate that the integration of geotechnical and geological information into a unified model can provide more reliable predictions of the subsurface stratification, by allowing simultaneous interpretation of USCS and Ic profiles. Importantly, the model demonstrates the potential to integrate multiple variables of different types, aiming to contribute to the development of a methodology for joint modeling of geotechnical, geological and geophysical data. T2 - 7th International Conference on Geotechnical and Geophysical Site Characterization CY - Barcelona, Spain DA - 18.06.2024 KW - Geotechnical site-characterization KW - Probabilistic KW - Soil classification KW - Gaussian Process PY - 2024 SP - 1733 EP - 1740 AN - OPUS4-60712 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 - 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 - Bronsert, Jeffrey A1 - Baeßler, Matthias A1 - Cuéllar, Pablo A1 - Rücker, Werner T1 - Numerische Modellierung der Fahrzeug-Fahrweg-Wechselwirkung an Brückenübergängen unter Berücksichtigung des Langzeitverhaltens N2 - In diesem Beitrag wird ein grundsätzliches Untersuchungskonzept für den Schienengebundenen Verkehr in Bezug auf das langzeitliche Verhalten am Brückenübergang vorgestellt. Das damit verbundene Ziel ist die Entwicklung eines numerischen Modells zu entwickeln, dass sowohl das Langzeitverhalten wie auch das kurzzeitdynamische Verhalten beschreibt, um konstruktive Lösungen zu entwickeln und zu optimieren. In einer ersten Phase wird der Brückenübergang mittels der FEM mit zwei unterschiedlichen Randmodellierungen für das FE-Gebiet modelliert. Die Ergebnisse der Modellierung mit einer Visko-Elastischen Randmodellierung und einer Randmodellierung mittels der Scaled-Boundary-Finite-Element Methode, werden miteinander verglichen. Unterschiede in der Wirkung auf kurzzeitdynamische Kenngrößen werden gezeigt, die heranzuziehen sind, um insbesondere Setzungen im Hinterfüllungsbereich des Brückenwiderlagers abzuschätzen. T2 - 4. VDI-Fachtagung - Baudynamik 2012 CY - Kassel, Germany DA - 25.04.2012 PY - 2012 SN - 978-3-18-092160-0 SN - 0083-5560 N1 - Serientitel: VDI-Berichte – Series title: VDI-Berichte VL - 2160 SP - 157 EP - 170 PB - VDI-Verl. CY - Düsseldorf AN - OPUS4-26980 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -