The foundation of offshore wind plants (OWEP) especially in the North Sea with water depths up to 30 m represent a technical challenge. In order to find an economical solution, the exact investigation of the structure's behaviour, particularly the long-term behaviour under cyclic loading from wave and wind should be studied. In this project numerical models will be developed to investigate the behaviour of the foundation of offshore wind plants based on modern studies related to the behaviour of soil under quasi-static or dynamic cyclic loading taking into account the interaction between the soil and the different types of foundation systems. Numerical models for the different foundation types (Gravity foundation, Monopile foundation, Tripod foundation) have been developed (Fig. 1).

A substantial aspect of this project is the realistic description of the soil behaviour under the repeated loading caused by waves and wind. A suitable material model is to be formulated and implemented by means of appropriate numeric algorithms into the program system ABAQUS. Further model developments are required to illustrate the behaviour of the soil and of the foundation system used under dynamic load.

Coordination:
Leibniz University of Hannover
Institute for Foundation Engineering, Soil Mechanics and Water Energy Structures
Appelstr. 9A
30167 Hannover
http://www.unics.uni-hannover.de/nhgwigbe
Project Manger:
Prof. Dr.-Ing. Martin Achmus
Project Coordinator:
Dr.-Ing. Khalid Abdel-Rahman
Tel.: 0511-762-2273
Email: khalid@igbe.uni-hannover.de

Course of the project:
01.08.2003 - 01.08.2008

[1] Achmus, M., Abdel-Rahman, K. (2004). Numerische Untersuchung zum Tragverhalten horizontal belasteter Monopile-Gründungen für Offshore- Windenergieanlagen. 19. Christian Veder Kolloquium, Graz, Österreich.

[2] Abdel-Rahman, K., Achmus, M. (2005). Numerische Untersuchung zum Tragverhalten von Bucketgründungen für Offshore-Windenergie-Anlagen. Abaqus Benutzerkonferenz, Nürnberg.

[3] Achmus, M., Abdel-Rahman, K. (2005). Design of Monopile Foundations for Offshore Wind Energy Plants. 11th International Colloquium on Structural and Geotechnical Engineerings, Cairo, Egypt.

[4] Achmus, M., Abdel-Rahman, K. (2005). Finite Element Modelling of Horizontally Loaded Monopile Foundations for Offshore Wind Energy Converters in Germany. In Susan Gourvenec, Mark Cassidy (Ed.), Proceedings of the International Symposium on Frontiers in Offshore Geotechnics (ISFOG), Perth, Australia. Taylor & Francis.

[5] Achmus, M., Abdel-Rahman, K., & Peralta, P. (2005). On the Design of Monopile Foundations with respect to Static and Quasi-Static Cyclic Loading. Copenhagen Offshore Wind 2005.

[6] Achmus, M., Abdel-Rahman, K., & Peralta, P. (2005). Untersuchungen zum Tragverhalten von Monopiles für die Gründung von Offshore-Windenergieanlagen. Pfahlsymposium, Braunschweig, Heft-Nr. 80.

[7] Achmus, M., Abdel-Rahman, K. (2005). Zum Tragverhalten von Monopile- und Bucketgründungen. Gigawind Symposium, Hannover, www.gigawind.de.

[8] Abdel-Rahman, K., Achmus, M. (2006). Behaviour of Monopile and Suction Bucket Foundation Systems for Offshore Wind Energy Plants. 5th International Engineering Conference, Sharm El-Sheikh, Egypt.

[9] Abdel-Rahman, K., Achmus, M. (2006). Numerical Investigations on the Bearing Capacity of Bucket Foundations under Combined Horizontal and Moment Loading. International Symposium on Ultimate Limit State of Geotechnical Structures.

[10] Abdel-Rahman, K., Achmus, M. (2006). Numerische Modellierung des Tragverhaltens von Offshore-Tripod-Gründungen. Abaqus-Benutzerkonferenz, Erfurt.

[11] Achmus, M., Abdel-Rahman, K., & Kuo, Y. (2007). Numerical Modelling of Large Diameter Steel Piles under Monotonic and Cyclic Horizontal Loading. 10th International Symposium on Numerical Models in Geomechanics, Rhodes, Greece.

[12] Achmus, M., Abdel-Rahman, K., Kuo, Y. & Peralta, P. (2007). Untersuchungen zum Tragverhalten von Monopilegründungen unter zyklischer Belastung. Pfahlsymposium, Braunschweig.

[13] Achmus, M., Abdel-Rahman, K. (2007). Numerical Modelling of Vertical Piles in Clay under Inclined Compression Loading. 12th International Colloquium on Structural and Geotechnical Engineering, Alexandria, Egypt.

[14] Achmus, M., Abdel-Rahman, K., Kuo, Y (2007). "Zur Bemessung von Pfählen für Offshore-Windenergieanlagen unter statischen und zyklischen Lasten", 5. Gigawind Symposium, Hannover, www.gigawind.de.

[15] K. Abdel-Rahman, Achmus, M. (2007)." Three Dimensional Numerical Modelling of Foundation Systems for Offshore Wind Energy Plants". Abaqus user Conference (AUC), Paris, France.

[16] K. Abdel-Rahman (2007) : "3-D numerische Modellierung von Offshore-Pfählen unter horizontaler mit verschiedenen Einwirkungsrichtungen", 19. Deutschsprachige Abaqus- Benutzerkonferenz, Baden-Baden.

[17] Achmus, M., Abdel-Rahman, K., Kuo, Y (2007). "Behaviour of Large Diameter Monopiles under cyclic horizontal Loading", 12th International Colloquium on Structural and Geotechnical Engineering, Cairo, Egypt.