The objective of the study was to provide recommendations to improve the conventional p-y method, API RP 2GEO (2014), for the design of laterally loaded monopiles in sand at small displacements. A three-dimensional Finite Element Method (FEM) model was developed to study the lateral stiffness of the monopiles using software Abaqus, incorporating a constitutive model simulating the small-strain behavior of sand measured from field and laboratory tests. The Mustang Island test was modeled by FEM approach and compared to the field measurement. p-y curves were extracted from the 3-D FEM models of piles with different diameters and were compared to them established based on conventional p-y method. The following conclusions could be drawn from the study: (1) the initial portion of the p-y curves for the laterally loaded monopiles should be revised and improved based on small-strain properties of site-specific soil; (2) the initial portion of the normalized Abaqus p-y curves is non-linear and higher than that developed by API RP 2GEO (2014); (3) The p-y curves can be normalized by the pile diameter. (4) The layer depth and pile diameter have little influence on the shape for the normalized p-y curves; (5) The L/D ratio has little contribution to the predicted load-displacement curve of the laterally loaded monopiles at small displacements.
Yunhan Huang, Robert Gilbert, Kenneth Stokoe, Shin-Tower Wang, James Munson, Jonas Bauer, Reihaneh Hosseini, Ahmed Hussien and Hossein Fadaifard
Keywords: Monopile, Offshore Wind, Small-strain Properties, P-y Curves
Publisher: DFI