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Foundation Design of The Buzzard Field Pile Foundation Design of Fixed Jacket Platform Zhangmou Li (2014215) E-mail: [email protected] Supervisor: Dr Bill Stewart Introduction The purpose of this project is design a foundation for a jacket fixed platform in Buzzard field. For the fixed structures, their foundations are classified with the water depth where the structures located, which has four main types: general multi-footing structures, deep foundation or pile foundation, shallow foundations and anchoring system. Figure 1 gives the graphic explanation for different types of deepwater structure. transverse loadings and settlements are shown in Figure 3 (a). in addition, the platform calculation module with the loading on leg toes is given in the Figure3 (b). (a) (b) Figure 3 soil distribution with properties and calculation module of the platform Pile foundation design results Figure 1 Seven types of offshore deepwater systems (Pongvithayapanu, 2010) Buzzard Field The Buzzard field was discovered in June 2001, which are located in the central North Sea where is approximately 50 km North-East of Peterhead of coast of Scotland with around 100 m water depth. Figure 2 shows the overviews of Buzzard filed and its location. Figure 2. The Buzzard field and location (Energy-pedia news, 2010) Geotechnical Investigation The geotechnical investigation of Buzzard field was performed by Fugro Limited. The basic properties of the soil which was used to calculate the resistance to both compressive and University of Glasgow, charity number SC004401 The foundation was designed in the worst circumstance based on both API and EC7 methods, and the pile’s material was BS 4360 Grade 55C steel with 2.5 m in diameter. Both of the foundations designed by American Petroleum Institute (API) method and Eurocode 7 (EC7) method were determined to contain 5 piles in group to carry the total loading from the superstructure, however, they had different embedment: for API method, the design embedment was over 36.6 m below the seabed; while, for EC7 method, the design embedment was only 24.1 m under the seabed. Also, they have a difference in settlements, API foundation will settle a length of 340.2 mm, and the EC7 foundation has a settlement of 155.9 mm. The both values of settlements are acceptable for this project. By comparing between API and EC7 method, there were three facts had been observed from the results: • The lateral behaviors of a pile is dominant compared with the axial behaviors. • API method is more conservative than EC7 • In EC 7 DA1 Combination 2 is more critical than Combination 1 References Energy-pedia news, 2010. UK: Output at Nexen's UKCS Buzzard oil field down due to production problem. [Online] Available at: http://www.energy-pedia.com/news/united-kingdom/output-atnexens-ukcs-buzzard-oil-field-down-due-to-production-problem [Accessed 22 8 2013] Pongvithayapanu, P., 2010. Offshore engineering: foundatioin of offshore structre. [Online] Available at: http://www.imc.src.ku.ac.th/personnel/file_subject/20101122955391.pdf [Accessed 26 5 2013].