The scope of study
Conical shell foundations are a well-known foundation system that has found its place in geotechnical engineering applications from time to time. From this point of view, the adaptation of conical shell foundations to wind turbine foundations has been evaluated.
Within the scope of the study, the geotechnical performances of a conventional shallow raft foundation and a circular conical shell foundation designed for an onshore wind turbine tower were compared for a single soil profile and in terms of the amount of structural material used in both foundations types. CSI-SAP2000 and ANSYS 2020 software were used for structural controls and PLAXIS 3D software was used for geotechnical solutions. According to the results of the study, it was evaluated that in the studied soil profile, circular conical shell foundation systems would be an economical alternative to shallow raft foundations and could find a place in the practice of the sector.
The finite element analysis performed to investigate the maximum principal stress values in conical and standard foundations is explained. The images of the models are shown in the figures.
The results of the study:
- When the sections are examined according to the structural analysis, it is understood that both foundation models have been damaged under the tensile stress values. It is seen that higher tensile stresses occur in the standard foundation compared to the conical shell foundation, and higher compressive stresses occur in the conical shell foundation compared to the standard foundation.
- According to the results of the geotechnical analysis, it was determined that the conical shell foundation offers more positive geotechnical performance values due to both its settlement in deeper layers and the greater contact surface.
- It is seen that the conical shell foundation behavior responds more positively under the overturning forces.
- It is seen that the conical shell foundation is a more economical solution in terms of the amount of material in the amount of concrete and rebar to be spent for the two foundation dimensions.
- The higher concrete quality requirement of the conical shell foundation and the relative labor difficulty in the field are issues that need improvement in the design.