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 - 2013-07-10 KW - Soil liquefaction KW - Cyclic loads KW - Piles KW - Sand (hydraulic) KW - Offshore structures PY - 2013 SN - 978-0-7844-1299-2 U6 - 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 - 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 U6 - 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 -