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 - 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 U6 - 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 - 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 - TY - CHAP A1 - Baeßler, Matthias A1 - Cuéllar, Pablo A1 - Georgi, Steven A1 - Karabeliov, Krassimire A1 - Rücker, Werner A1 - Johnsen, Björn ED - Durstewitz, M. ED - Lange, B. T1 - Uncharted Territory on the Seabed - Monitoring Procedures and Assessment Model for the Foundations of Offshore Wind Turbines N2 - Offshore wind turbines enter unknown territory, especially where the foundations are concerned. This is because offshore wind power can only make use of the experience from the common offshore constructions used by the oil and gas industry to a limited extent. The offshore wind industry has tried to reduce foundation dimensions, especially the pile lengths, as much as possible compared with those of the oil and gas industry. This is because with the large number of wind turbines involved it can provide considerable economic advantages. On the other hand, the stability of the foundations is additionally at risk because due to the much larger number of cyclic loads they are subjected to it is very difficult to predict how they will behave. Since offshore wind farms are manufactured in series, every systematic fault in the foundation acts as a series fault for a large number of turbines. This calls for monitoring – and the right dimensions of pile foundation, the most common type of foundations used for wind turbines KW - Offshore wind turbines KW - Field tests KW - Axial pile capacity PY - 2017 SN - 978-3-662-53178-5 U6 - https://doi.org/10.1007/978-3-662-53179-2 SP - 61 EP - 67 PB - Springer AN - OPUS4-39341 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -