Increasing the Available Soil Rotational Stiffness using Rammed Aggregate Piers for Wind Turbine Foundations Applications

Abstract

Wind turbine foundations must be designed to limit the angular rotation of the tower. Rammed Aggregate Piers (RAPs) are commonly used as a mean for increasing the available soil rotational stiffness by taking advantage of their higher stiffness compared to that of the matrix soil being reinforced. A composite stiffness approach using the elastic dynamic parameters of the soil and the RAP elements is used to develop a solution for increasing the foundation soil available rotational stiffness, thereby meeting the project design requirements. This article presents the technical background and procedures used for developing a solution for increasing the foundation soil rotational stiffness using Rammed Aggregate Piers for support of wind turbine foundations. A case history example is also presented at the end to support the technical discussion. Key Terms - Ground Improvement, Rammed Aggregate Piers, Soil Rotational Stiffness, Wind Turbine Foundations.