- Volume 10 Issue 5
DOI QR Code
Static impedance functions for monopiles supporting offshore wind turbines in nonhomogeneous soils-emphasis on soil/monopile interface characteristics
- Abed, Younes (Department of Civil Engineering, Faculty of Technology, University Saad Dahled of Blida) ;
- Bouzid, Djillali Amar (Department of Civil Engineering, Faculty of Technology, University Saad Dahled of Blida) ;
- Bhattacharya, Subhamoy (Department of Civil and Environmental Engineering, Tomas Telford Building, University of Surrey) ;
- Aissa, Mohammed H. (Department of Material Engineering, Faculty of Sciences and Technology, University of Medea)
- Received : 2015.07.29
- Accepted : 2016.04.01
- Published : 2016.05.25
Offshore wind turbines are considered as a fundamental part to develop substantial, alternative energy sources. In this highly flexible structures, monopiles are usually used as support foundations. Since the monopiles are large diameter (3.5 to 7 m) deep foundations, they result in extremely stiff short monopiles where the slenderness (length to diameter) may range between 5 and 10. Consequently, their elastic deformation patterns under lateral loading differ from those of small diameter monopiles usually employed for supporting structures in offshore oil and gas industry. For this reason, design recommendations (API and DNV) are not appropriate for designing foundations for offshore wind turbine structures as they have been established on the basis of full-scale load tests on long, slender and flexible piles. Furthermore, as these facilities are very sensitive to rotations and dynamic changes in the soil-pile system, the accurate prediction of monopile head displacement and rotation constitutes a design criterion of paramount importance. In this paper, the Fourier Series Aided Finite Element Method (FSAFEM) is employed for the determination of static impedance functions of monopiles for OWT subjected to horizontal force and/or to an overturning moment, where a non-homogeneous soil profile has been considered. On the basis of an extensive parametric study, and in order to address the problem of head stiffness of short monopiles, approximate analytical formulae are obtained for lateral stiffness
semi-analytical FE analysis;laterally loaded short monopiles;monopile head stiffnesses;offshore wind turbines;natural frequency
- Achmus, M., Kuo, Y.-S. and Abdel-Rahman, K. (2009), "Behavior of monopile foundations under cyclic lateral load", Comput. Geotech., 36(5), 725-735. https://doi.org/10.1016/j.compgeo.2008.12.003
- Adhikari, S. and Bhattacharya, S. (2011), "Vibrations of wind-turbines considering soil-structure interaction", Wind Struct., 14(2), 85-112. https://doi.org/10.12989/was.2011.14.2.085
- Adhikari, S. and Bhattacharya, S. (2012), "Dynamic analysis of wind turbine towers on flexible foundations", Shock Vib., 19(1), 37-56. https://doi.org/10.1155/2012/408493
- Al Hamaydeh, M. and Hussain, S. (2011), "Optimized frequency-based foundation design for wind turbine towers utilizing soil-structure interaction", J. Franklin Inst., 348(7), 1470-1487. https://doi.org/10.1016/j.jfranklin.2010.04.013
- Amar Bouzid, Dj. (1997), "Analyse semi-analytique par elements finis des pieux isoles sollicites horizontalement dans un milieu a comportement non-lineaire", These de Magister, Ecole Nationale Polytechnique, Alger, Algerie.
- Amar Bouzid, Dj., Tiliouine, B. and Vermeer, P.A. (2004), "Exact formulation of interface stiffness matrix for axisymmetric bodies under non-axisymmetric loading", Comput. Geotech., 31(2), 75-87. https://doi.org/10.1016/j.compgeo.2004.01.007
- American petroleum Institute (API) and International Organization for Standardization (ISO) (2011), ANSI/API Specification RP 2GEO, Geotechnical Considerations and Foundation Design for Offshore Structures. Washington, DC.
- Andersen, L.V., Vahdatirad, M.J., Sichani, M.T. and Sorensen, J.D. (2012), "Natural frequencies of wind turbines on monopile foundations in clayey soils-A probabilistic approach", Comput. Geotech., 43, 1-11. https://doi.org/10.1016/j.compgeo.2012.01.010
- Bhattacharya, S. (2011), SDOWT: Simplified Dynamics of Wind Turbines, User's Manual, Bristol Laboratory for Advanced Dynamics Engineering, Bristol, UK.
- Bhattacharya, S. (2014), "Challenges in design of foundations for offshore wind turbines", Eng. Technol. Reference, 1(1), 1-9.
- Bhattacharya, S., Cox, J.A., Lombardi, D. and Wood, D.M. (2013), "Dynamics of offshore wind turbines supported on two foundations", Proc. Inst. Civ. Eng.: Geotech. Eng., 166(GE2), 159-169. https://doi.org/10.1680/geng.11.00015
- Bisoi, S. and Haldar, S. (2015), "Design of monopile supported offshore wind turbine in clay considering dynamic soil-structure-interaction", Soil Dyn. Earthq. Eng., 73, 103-117. https://doi.org/10.1016/j.soildyn.2015.02.017
- Booker, J.R., Baalam, N.P. and Davis, E.H. (1985), "The behavior of an elastic non-homogenous halfspace", Int. J. Numer. Anal. Meth. Geomech., 353-367.
- Burland, J.B., Sills, G.C. and Gibson, R.E. (1973), "A field and theoretical study of the interface of nonhomogeneity on settlement", Proceedings of the 8th International Conference on Soil Mechanics, Moscow.
- Cole, K.W. and Burland, J.B. (1972), "Observations of retaining wall movements associated with a large excavation", Proceedings of 5th European Conference on Soil Mechanics, Madrid.
- Cook, R.D., Malkus, D.S., Plesha, M.E. and Witt, R.J. (2002), Concepts and Applications of Finite Element Analysis, Joh Wiley and Sons inc., New York, USA.
- Cuellar, P., Georgi, S., Baessler, M. and Rucker, W. (2012), "On the quasi-static granular convective flow and sand densification around pile foundations under cyclic lateral loading", Granular Matter, 14(1), 11-25. https://doi.org/10.1007/s10035-011-0305-0
- Damgaard, M., Bayat, M., Andersen, L.V. and Ibsen, L.B. (2014), "Assessment of the dynamic behavior of saturated soil subjected to cyclic loading from offshore monopile wind turbine foundations", Comput. Geotech., 61, 116-126. https://doi.org/10.1016/j.compgeo.2014.05.008
- Damgaard, M., Bayat, M., Andersen, L.V. and Ibsen, L.B. (2015), "Dynamic response sensitivity of an offshore wind turbine for varying subsoil conditions", Ocean Eng., 101, 227-234. https://doi.org/10.1016/j.oceaneng.2015.04.039
- Davies, T.G. and Budhu, M. (1986), "Non linear analysis of laterally loaded piles in heavily overconsolidated clays", Geotechnique, 36(4), 527-538. https://doi.org/10.1680/geot.19126.96.36.1997
- Det Norske Veritas (2004), DNV-OS-J101 Offshore standard: Design of offshore wind turbine structures, Hellrup, Danmark: DNV.
- Durocher, L.A., Gasper, A. and Rhoades, G. (1978), "A numerical comparison of axisymmetric finite elements", Int. J. Numer. Meth. Eng., 12(9), 1415-1427. https://doi.org/10.1002/nme.1620120910
- Gazetas, G. (1991), Foundation vibrations, In Foundation Engineering Handbook, 2nd Edition, Ed., Fang, HY., Van Nostrand Reinhold, New York, 553-593.
- GL (2005), Rules and guidelines-Industrial services, Germanischer Lloyd.
- Griffiths, D.V. and Lane, P.A. (1990), "Finite element analysis of the shear vane test", Comput. Struct., 37(6), 1105-1116. https://doi.org/10.1016/0045-7949(90)90022-T
- Higgins, W., Vasquez, C., Basu, D. and Griffiths, D.V. (2013), "Elastic solutions for laterally loaded piles", J. Geotech. Geoenviron. Eng., 139(7), 1096-1103. https://doi.org/10.1061/(ASCE)GT.1943-5606.0000828
- Hooper, J.A. (1973), "Observations on the behavior of a piled raft foundation on London clay", Proceeding of the Institution Civil Engineering.
- Laszlo, A., Bhattachary, S., Hogan, S.J. and Macdonald, J. (2014), "Dynamic soil-structure interaction issues of offshore wind turbines", Proceedings of the 9th International Conference on Structural Dynamics, Porto, Portugal.
- Leblanc, C. (2009), "Design of offshore wind turbine support structures-selected topics in the field of geotechnical engineering", Aalborg University, Denmark.
- Lombardi, D., Bhattacharya, S. and Wood, D.M. (2013), "Dynamic soil-structure interaction of monopile supported wind turbines in cohesive soil", Soil Dyn. Earthq. Eng., 49, 165-180. https://doi.org/10.1016/j.soildyn.2013.01.015
- Luqing, Y., Bhattacharya, S., Lingling, L. and Zhen, G. (2014), "Dynamic characteristics of offshore wind turbines on different types of foundations", Electron. J. Geotech. Eng., 19, 2917-2936.
- Matlock, H. (1970), "Correlations for design of laterally loaded piles in soft clay", Proceedings of the Offshore Technology Conference, Houston, Texas.
- Murchison, J.M. and O'Neill, M.W. (1984), "Evaluation of p-y relationships in cohesionless soils", Analysis and Design of Pile Foundations, Proceedings of a Symposium in conjunction with the ASCE National Convention, pp. 174-191.
- Myers, A.T., Arwade, S.R., Valamanesh, V., Hallowell, S. and Carswell, W. (2015), "Strength, stiffness, resonance and the design of offshore wind turbine monopoles", Eng. Struct., 100, 332-341. https://doi.org/10.1016/j.engstruct.2015.06.021
- Potts, D.M. and Zdrackovic, L. (1999), Finite Element Analysis in Geotechnical Engineering: Theory. Thomas Telfor Publishing, Heron Quay, London, UK.
- Poulos, H.G. and Hull, S.T. (1989), "Analytical geomechanics in foundation engineering-A study of laterally loaded piles", Research Report No. R667. School of Civil and Mining Engineering, Sydney University.
- Poulos, H.G. and Davis, E.H. (1980), Pile foundation analysis and design, Wiley, NewYork, USA.
- Prendergast, L.J., Gavin, K. and Doherty, P. (2015), "An investigation into the effect of scour on the natural frequency of an Offshore Wind Turbine", Ocean Eng., 101, 1-11 https://doi.org/10.1016/j.oceaneng.2015.04.017
- Randolph, M.F. (1981), "The response of flexible piles to lateral loading", Geotechnique, 31(2), 247-259. https://doi.org/10.1680/geot.19188.8.131.52
- Reese, L., Cox, W.R. and Koop, F.D. (1974), "Analysis of laterally loaded piles in sand", OTC 2079, Proceedings of the Offshore Technology Conference, Houston, USA.
- Shirzadeh, R., Devriendt, C., Bidakhvidi, M.A. and Guillaume, P. (2013), "Experimental and computational damping estimation of an offshore wind turbine on a monopile foundation", J. Wind Eng. Indust. Aerodyn., 120, 96-106. https://doi.org/10.1016/j.jweia.2013.07.004
- Tempel, D.P. and Molenaar, D.P. (2002), "Wind turbine structural dynamics-a review of the principles for modern power generation, onshore and offshore", Wind Eng., 26(4), 211-220. https://doi.org/10.1260/030952402321039412
- Vught, J.H. (2000), "Considerations on the dynamics of support structures for an offshore wind energy converters", Ph.D thesis, Delft University of Technology, The Netherlands.
- Wilson, E.L. (1965), "Structural analysis of axisymmetric solids", J. Am. Inst. Aeronaut Astronaut, 3(12), 2269-2274. https://doi.org/10.2514/3.3356
- Winnicki, L.A. and Zienkiewicz, O.C. (1979), "Plastic (or visco-plastic) behavior of axisymmetric bodies subjected to non-axisymmetric loading, semi-analytical finite element solution", Int. J. Numer. Meth. Eng., 14(9), 1399-1412. https://doi.org/10.1002/nme.1620140911
- Yi, Jin-Hak, Sun-Bin, Kim, Gil-Lim, Yoon and Lars Vabbersgaard, Andersen (2015), "Natural frequency of bottom-fixed offshore wind turbines considering pile-soil-interaction with material uncertainties and scouring depth", Wind Struct., 21(6), 625-639. https://doi.org/10.12989/was.2015.21.6.625
- Yu, Lu-Qing, Li-Zhong, Wang, Zhen, Guo, S., Bhattacharya, G., Nikitas, Ling-Ling, Li and Yue-Long, Xing (2015), "Long-term dynamic behavior of monopile supported offshore wind turbines in sand", Theo. Appl. Mech. Lett., 5(2), 80-84. https://doi.org/10.1016/j.taml.2015.02.003
- Zienkiewicz, O.C. and Taylor, R.L. (2000), The Finite Element Method, Butterworth-Heinemann, London, UK.
- Soil–Structure Interactions for Offshore Wind Turbines vol.1, pp.1, 2012, https://doi.org/10.1049/etr.2016.0019
- Design of monopiles for offshore wind turbines in 10 steps vol.92, 2017, https://doi.org/10.1016/j.soildyn.2016.09.024
- A numerical procedure to correlate the subgrade reaction coefficient with soil stiffness properties for laterally loaded piles using the FSAFEM 2017, https://doi.org/10.1080/19386362.2017.1365475
- Monopile head stiffness for servicibility limit state calculations in assessing the natural frequency of offshore wind turbines 2017, https://doi.org/10.1080/19386362.2016.1270794
- An Efficient FE model for SSI: Theoretical background and assessment by predicting the response of large diameter monopiles supporting OWECs vol.97, 2018, https://doi.org/10.1016/j.compgeo.2017.12.001
- Impedance Functions for Double-D-Shaped Caisson Foundations vol.47, pp.3, 2018, https://doi.org/10.1520/JTE20180075
- Curves vol.18, pp.11, 2018, https://doi.org/10.1061/(ASCE)GM.1943-5622.0001204