Cyclic Response of OWT Pile Foundations in Sand: Numerical Simulation of PISA Field Tests


Panagiota Tasiopoulou, Jacob Chacko, Yannis Chaloulos, Amalia Giannakou and Nikos Gerolymos have co-authored a paper titled: “Insight into the Cyclic Response of OWT Pile Foundations in Sand: Numerical Simulation of PISA Field Tests” which has been published in the Proceedings of the 4th International Symposium on Frontiers in Offshore Geotechnics (ISFOG 2020) in Austin, Texas. This paper presents numerical simulations of selected field tests of monopiles in Dunkirk sand conducted as part of the PISA program, in the finite difference code FLAC 3D using the Ta-Ger constitutive model for sand. The simulated tests included medium diameter piles which were subjected to both monotonic and cyclic lateral and overturning loading. Comparison between numerical results and test measurements show that the simulations can reproduce the basic mechanisms of the monopile/soil system response, under both monotonic and cyclic loading. Features reproduced in the simulations include the increase of the system stiffness during cyclic loading and the associated decreasing rate of accumulation of lateral displacement and rotation. Lateral soil support in terms of p-y curves as well as distributed moment due to vertical shear stresses along the pile perimeter were obtained from the numerical analysis. It is shown that the numerical methodology can be used to gain insight into soil-OWT foundation interaction mechanisms and derive the soil reactions acting on the foundations as a result of lateral and overturning loads.

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