Develop and verify soil/structure interaction for pile/foundation interaction

**Overview**

Phase II of the Offshore Code Comparison Collaboration, Continued, with Correlation and unCertainty (OC6) project was used to verify the implementation of a new soil-structure interaction (SSI) model for use within offshore wind turbine modeling software. The REDWIN Macro-element model implemented and verified in this study enables a computationally efficient way to model the linear and nonlinear SSI problem, including hysteretic damping, of a monopile structure. The modeling approach was integrated into several modeling tools and a series of increasingly complex simulations was conducted using the IEA 10MW reference turbine mounted on a monopile support structure to verify the coupling between the tools and the REDWIN Macro-element SSI model. This campaign includes only numerical verification between various software and modeling approaches so no experimental measurements are available. The load cases (LC) considered include:

LC1 ? static response of the tower and substructure

LC2 ? frequency and mode-shape analysis of the tower and substructure

LC3 ? response of the tower and substructure due to wind-only loading

LC4 ? response of the tower and substructure due to wave-only loading

LC5 ? response of the tower and substructure due to wind and wave loading.

Detailed properties of the modeled system are found in the following reference, ?Bergua, Roger, Amy Robertson, Jason Jonkman, and Andy Platt. 2021. "Specification Document for OC6 Phase II: Verification of an Advanced Soil-Structure Interaction Model for Offshore Wind Turbines.? Golden, CO: National Renewable Energy Laboratory. NREL/TP-5000-79938. https://www.nrel.gov/docs/fy21osti/79938.pdf.

Details on the results from the OC6 Phase II project can be found in the following reference, ?Bergua R, Robertson A, Jonkman J, et al. OC6 Phase II: Integration and verification of a new soil?structure interaction model for offshore wind design.? Wind Energy. 2022;25(5):793-810. doi:10.1002/we.2698


**Data Details**

Nineteen academic and industrial partners performed simulations as part of this project, and their simulation results are available on this website. The naming of the datafiles follows the convention: oc6.phase2.participant.loadcase.txt. Also included are the wind files used by participants to prescribe forces and moments at the tower top yaw bearing for average hub-height wind speeds of 9.06 m/s and 20.09 m/s. These files are named as ?IEA-10.0-198-RWT_Uref09p06.txt? and ?IEA-10.0-198-RWT_Uref20p09.txt? respectively.

OC6 Phase II data files have an identifier after the participant corresponding to the modeling approach used. These identifiers are defined as followed:

M1: Apparent Fixity (AF)

M2: Coupled Springs (CS)

M3: Distributed Springs (DS)

M4: REDWIN

**Data Quality**

This was a verification study with only simulation results. Data quality and uncertainty statements apply only to experimental data.