Centrifuge Modeling of Monopiles Subjected to Lateral Monotonic Loading

Authors: H. R. Khodaei, M. Moradi, A. H. Tajik

Abstract:

The type of foundation commonly used today for berthing dolphins is a set of tubular steel piles with large diameters, which are known as monopiles. The design of these monopiles is based on the theories related with laterally loaded piles. One of the most common methods to analyze and design the piles subjected to lateral loads is the p-y curves. In the present study, centrifuge tests are conducted in order to obtain the p-y curves. Series of tests were designed in order to investigate the scaling laws in the centrifuge for monotonic loading. Also, two important parameters, the embedded depth L of the pile in the soil and free length e of the pile, as well as their ratios were studied via five experimental tests. Finally, the p-y curves of API are presented to be compared with the curves obtained from the tests so that the differences could be demonstrated. The results show that the p-y curves proposed by API highly overestimate the lateral load bearing capacity. It suggests that these curves need correction and modification for each site as the soil conditions change.

Keywords: Centrifuge modeling, monopile, lateral loading, p-y curves.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1315839

References:

[1] A. S. Hokmabadi, A. Fakher, B. Fatahi, “Full scale lateral behavior of monopiles in granular marine soils”, Marine Structures Journal, pp 1-13, 2012.
[2] W. G. K. Fleming, A. J. Weltman, M. F. Randolph, and W. K. Elson, “Piling Engineering”, 2nd edition , Blackie Academic & Professional, Glasgow, UK, 1992.
[3] H. Matlock, L. C. Reese, “Generalized solution for laterally loaded piles”, Soil Mechanics and Foundation Journal. Vol 86(5):673-94, ASCE, 1961.
[4] H. G. Poulos, E. H. Davis, “Pile Foundation Analysis and Design”, John Wiley & Sons, USA, 1980.
[5] L. C. Reese, E. D. Koop, “Analysis of laterally loaded piles in sand”, 6th Annual Offshore Technology Conf., 1974.
[6] J. M. Murchison, M. W. O’Neill, “Evaluation of p-y relationships in cohesionless soil”, Analysis and Design of Pile Foundations, New York, USA, ASCE, p. 91-174, 1984.
[7] API “Recommended Practice for Planing, Designing and Constructing of Fixed Offshore Platforms” WSD 2007.
[8] S. A. Ashford, T. Juirnarongrit, “Evaluation of pile diameter effect on initial modulus of subgrade reaction”, Journal of Geotechnical and Geoenvironmental Engineering, Vol 129, no. 3, pp. 234-242, 2003.
[9] M. Ashour, G. Norris, “Refinement of the strain wedge method program”, Department of Transportation, Report CCEER 99-08, State of California, USA, 1999.
[10] R. Klinkvort, O. Hededal, “Centrifuge modelling oh offshore monopole foundation”, Frontiers in Offshore Geotechnics II – Gourvenec & Seward (eds), Taylor & Francis -Group, London, pp 581-586, 2011.
[11] K. Lensy, S. G. Paikowsky, A. Gurbuz, “Scale effects in lateral load response of large diameter monopiles”, Geo-Denver, New Peaks in Geotechnics, ASCE, Colorado, 2007.
[12] E. A. Alderlieste, “Experimental Modelling of Lateral Loads on Large Diameter Monopile Foundations In Sand”, Master of Science Thesis, Civil Engineering at Delft University of Technology, Netherland, 2011.
[13] M. Rojhani, “Response of embedded continuous pipelines subject to faulting centrifuge modeling”, Ph.D. Thesis, Civil Engineering Faculty, Tehran University, Tehran, Iran, 2012 (In Persian)
[14] P. L. Bransby, I. A. A. Smith, “The effects of side friction in model retaining wall experiments”, Cambridge University, Engineering Department, Vol 17 of CUED/C – Soils/TR, 66 pages, 1973.
[15] American Society for Testing and Materials, “Standard method of testing piles under lateral loads”, Annual Book of ASTM Standards, D3966-90. ASTM, 2013.