Augustesen, Anders Hust

Brodbaek, K. T.

Ibsen, Lars Bo

Moller, M.

Sørensen, Søren Peder Hyldal

English

For laterally loaded piles in sand with diameters up to 6 m, e.g. monopiles used as foundations for offshore wind turbines, there is no approved design procedure. The p-y curve method, given in offshore design regulations, is usually employed for the design of monopiles. However, this method was developed for slender piles with diameters much less than 6 m and it is based on a limited number of tests. The aim of the present work is to extend the p-y curve method to large-diameter non-slender piles by considering the effects of the pile diameter on the soil response. The main focus is the initial stiffness of the p-y curves. The evaluation is based on experimental work as well as three-dimensional numerical analyses in the commercial programme FLAC3D.For laterally loaded piles in sand with diameters up to 6 m, e.g. monopiles used as foundations for offshore wind turbines, there is no approved design procedure. The p-y curve method, given in offshore design regulations, is usually employed for the design of monopiles. However, this method was developed for slender piles with diameters much less than 6 m and it is based on a limited number of tests. The aim of the present work is to extend the p-y curve method to large-diameter non-slender piles by considering the effects of the pile diameter on the soil response. The main focus is the initial stiffness of the p-y curves. The evaluation is based on experimental work as well as three-dimensional numerical analyses in the commercial programme FLAC3D.</em

Evaluation of the Load-Displacement Relationships for Large-Diameter Piles in Sand

Brødbæk, K. T.

Møller , M.

    Aalborg UniversitetEvaluation of the Load-Displacement Relationships for Large-Diameter Piles in SandSørensen, Søren Peder Hyldal; Brodbaek, K. T.; Moller, M.; Augustesen, Anders Hust; Ibsen,Lars BoPublished in:Proceedings of the Twelfth International Conference on Civil, Structural and Environmental EngineeringComputingPublication date:2009Document VersionPublisher's PDF, also known as Version of recordLink to publication from Aalborg UniversityCitation for published version (APA):Sørensen, S. P. H., Brodbaek, K. T., Moller, M., Augustesen, A. H., & Ibsen, L. B. (2009). Evaluation of theLoad-Displacement Relationships for Large-Diameter Piles in Sand. In B. H. V. Topping, L. F. C. Neves, & R. C.Barros (Eds.), Proceedings of the Twelfth International Conference on Civil, Structural and EnvironmentalEngineering Computing Civil-Comp Press. Civil-Comp Proceedings No. 91General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright ownersand it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.            ? Users may download and print one copy of any publication from the public portal for the purpose of private study or research.            ? You may not further distribute the material or use it for any profit-making activity or commercial gain            ? You may freely distribute the URL identifying the publication in the public portal ?Take down policyIf you believe that this document breaches copyright please contact us at vbn@aub.aau.dk providing details, and we will remove access tothe work immediately and investigate your claim.Downloaded from vbn.aau.dk on: November 29, 2020 Proceedings home preface contents authors keywords copyright reference ©2009 Civil-Comp Ltd CDROM ISBN 978-1-905088-31-7 Paper 244  Evaluation of the Load-Displacement Relationships for Large-Diameter Piles in Sand  S.P.H. Sorensen, K.T. Brodbaek, M. Moller, A.H. Augustesen and L.B. Ibsen  Department of Civil Engineering, Aalborg University, Denmark  Keywords: monopile, sand, p-y curves, Winkler model approach, geotechnical engineering, FLAC3D, laboratory tests.  full paper (pdf) - reference  For laterally loaded piles in sand with diameters up to 6m, for example monopiles used as foundations of offshore wind turbines, there is no approved design procedure. The p-y curve method, given in offshore design regulations, is usually employed for the design of monopiles. However, this method was developed for slender piles with diameters much less than 6m and it is based on a limited number of tests.  The aim of the present work is to extend the p-y curve method to large-diameter non-slender piles by considering the effects of the pile diameter on the soil response. The main focus is the initial stiffness of the p-y curves. The evaluation is based on experimental work as well as three-dimensional numerical analyses. The numerical analyses are made by means of the commercial programme FLAC3D. A Mohr-Coulomb material model is employed. The numerical model is calibrated using six small-scale tests conducted on heavily instrumented piles with diameters varying from 60-80 mm subjected to a horizontal load. The tests are carried out in a pressure tank at different effective stress levels in order to simulate realistic effective vertical stresses for a typical monopile. After calibrating the model using small-scale tests the numerical model is extended to full-scale wind turbine foundations. The results are compared with results obtained from a traditional p-y curve design based on a Winkler model approach.  Major findings of this paper are:  1. The initial stiffness of the p-y curves increases for increasing pile diameter.  2. The initial modulus of subgrade reaction given by the offshore design regulations is overestimated for large diameter non-slender piles.  3. A linear variation of the initial stiffness with depth is a non-conservative estimation at large depths  4. The power function proposed by Lesny and Wiemann [1] describing the variation of initial stiffness with depth provides reasonable results compared with the three-dimensional numerical model.  References  K. Lesny, J. Wiemann, "Finite-Element-Modelling of Large Diameter Monopiles for Offshore Wind Energy Converters", Geo Congress 2006, February 26 to March 1, Atlanta, GA, USA, 2006.  1Side 1 af 1Proceedings of CC2009 - 244 Evaluation of the Load-Displacement Relationships for ...20-11-2009file://D:\html\summary\sorenson.htm

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Evaluation of the Load-Displacement Relationships for Large-Diameter Piles in Sand

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