Presentation Title

Renewable Energy from Offshore Wind Turbines using Multi Anchor Foundations

Faculty Mentor

Dr. John McCartney

Start Date

23-11-2019 10:00 AM

End Date

23-11-2019 10:45 AM

Location

177

Session

poster 3

Type of Presentation

Poster

Subject Area

engineering_computer_science

Abstract

Offshore wind turbines are a promising approach to collect renewable energy. When used in tandem with a monopile foundation, they are often limited to placement in shallow water hampering their potential. The objective of this project is to perform various analyses to determine the mechanical properties of alternative foundation systems to the monopile. A new idea is to use a multi-anchor foundation system, which consists of helical anchors connected with a truss that will permit placement of wind turbines in greater water depths. Helical anchors have a shape similar to a screw and are installed into the seabed using rotary drill with a torque measurement. The installation torque can be used to estimate the ultimate capacity of anchors under axial tension or compression loading, which can be compared with expected loading from ocean waves. However, the long-term cyclic loading response of the installed anchors under smaller wave loading should also be evaluated. The upward displacement response during long-term cyclic loading is a function of pile geometry, the number and spacing helices, loading frequency, and load amplitude. The accuracy of an existing torque model based on the commonly performed cone penetration test (CPT) was examined against a database of installations performed at NAVFAC. The model matched the experimental database well for a variety of soil conditions, and will help evaluate installation requirements as helical anchors are upscaled for offshore usage.

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Nov 23rd, 10:00 AM Nov 23rd, 10:45 AM

Renewable Energy from Offshore Wind Turbines using Multi Anchor Foundations

177

Offshore wind turbines are a promising approach to collect renewable energy. When used in tandem with a monopile foundation, they are often limited to placement in shallow water hampering their potential. The objective of this project is to perform various analyses to determine the mechanical properties of alternative foundation systems to the monopile. A new idea is to use a multi-anchor foundation system, which consists of helical anchors connected with a truss that will permit placement of wind turbines in greater water depths. Helical anchors have a shape similar to a screw and are installed into the seabed using rotary drill with a torque measurement. The installation torque can be used to estimate the ultimate capacity of anchors under axial tension or compression loading, which can be compared with expected loading from ocean waves. However, the long-term cyclic loading response of the installed anchors under smaller wave loading should also be evaluated. The upward displacement response during long-term cyclic loading is a function of pile geometry, the number and spacing helices, loading frequency, and load amplitude. The accuracy of an existing torque model based on the commonly performed cone penetration test (CPT) was examined against a database of installations performed at NAVFAC. The model matched the experimental database well for a variety of soil conditions, and will help evaluate installation requirements as helical anchors are upscaled for offshore usage.