Foundations for offshore wind towers Marissa Blakley YES Prep Public Schools – East End Campus Houston, Texas Dr. Giovanna Biscontin & Dr. Charles Aubeny Department of Civil Engineering

Dr. giovanna biscontin Associate Professor, Department of Civil Engineering Bachelors Degree from the University of Padova, Italy Masters Degree from the University of California, Berkeley PhD from the University of California, Berkeley Research Interests: Dynamic response of soils, earthquake engineering, seismic slope stability, experimental methods for characterization of soil behavior, numerical methods and modeling in geomechanics, soft soils, offshore geotechnics, and deep soil mixing. https://ceprofs.civil.tamu.edu/gbiscontin/

Dr. charles aubeny Associate Professor, Geotechnical Engineering Bachelors Degree from the University of Arizona Masters Degree from the University of Colorado at Denver PhD from the Massachusetts Institute of Technology Research Interests: Foundations and anchors for offshore structures, offshore risers and pipelines, slopes and retaining walls, dams and levees, expansive soils, and numerical methods in geotechnical engineering. https://ceprofs.civil.tamu.edu/caubeny/

The research team Madahuri Murali Marissa Blakley Silvia Vital Francisco Grajales Ryan Beemer

Geotechnical engineering A branch of civil engineering concerned with the engineering behavior of earth materials that uses principles of soil and rock mechanics http://en.wikipedia.org/wiki/Geotechnical_engineering

Geotechnical engineering Investigate subsurface conditions and materials. Determine the relevant physical, mechanical and chemical properties of these materials. Evaluate stability of natural slopes and man-made soil deposits. Assess risks posed by site conditions. Design earthworks and structure foundations.

Importance of Geotechnical engineering Railway Track Failure due to Earthquake Loading Leaning Tower of Pisa Italy Natural Disasters such as Vaoint Dam in Italy http://whatiscivilengineering.csce.ca/geotechnical.htm

Why offshore geotechnical engineering? Population density in 2007 Esteban, 2011

Why offshore geotechnical engineering? Population density in 2030 Esteban, 2011

Common offshore oil-gas systems Texas A&M University, Department of Civil Engineering

Why offshore wind energy? With more and more interest in renewable energy sources, countries have begun to look offshore to fulfill energy needs. Currently, wind energy makes up 2% of the global energy supply and is expected to grow by 160% in the next five years. By 2050, 80% of the world’s energy supply in developing countries could come from renewable sources with wind playing a major role in electricity generation. http://www.treehugger.com/corporate-responsibility/offshore-wind-farms-to-power-15th-of-europe-by-2030.html Sun, 2012

Offshore benefits Usher in a new industry and economic development Support our nation’s goal of energy security Support the fight against climate change Stabilize power prices Eliminates more than 650,000 tons/year of carbon dioxide Diversification of energy Wind over water is stronger, more consistent & smoother than wind over land Less concern regarding noise & visual appeal

Wind turbines One 1.8 megawatt wind turbine can produce up to 4.7 million units of electricity per year. This amount could meet the annual needs of up to 1,000 households.

Construction of an offshore wind turbine

The research question How does the monopile’s interaction with the soft clay at the bottom of the ocean affect the stabilization of the wind turbine?

Our problem The strong lateral forces present at sea cause wind turbines to vibrate, or rock back and forth. These vibrations cause the soil at the bottom of the ocean to weaken, creating a vertical angle between the pile and ocean floor. If this angle exceeds 5o, the wind turbine stops producing energy. Texas A&M University, Department of Civil Engineering

The research goal Characterize the behavior of soil so that engineers can make smart, sustainable choices when constructing offshore wind farms. http://inhabitat.com/

T-bar test Voltage * Calibration Factor = Force

T-bar data collection Time(s) Volts -1.49E-08 0.05 4.02E-07 0.1 -1.49E-08 0.05 4.02E-07 0.1 -7.82E-07 0.15 -1.27E-06 0.2 -1.12E-06 0.25 -2.26E-06 0.3 -1.06E06 0.35 -2.98E07 0.4 -1.33E06

Mini-shear vane test Voltage * Calibration Factor = Torque

Project summary Based on the new market of offshore wind energy, we must study the interaction between the wind turbine’s monopile and the soft clays at the ocean floor. Studying these interactions will allow engineers to make cost- effective and sustainable decisions when installing wind farms in the near future.

Classroom connections Student-Constructed Wind Turbines Soil Strength Simulation 20-gallon aquarium filled with multi-colored sand Vertical force applied to sand Students able to see when soil fails Student-Led Data Collection Using Custom-Built Pressure Gauge PreCalculus Data and Functional Analysis

acknowledgements

Special thanks Dr. Giovanna Biscontin Dr. Charles Aubeny Ryan Beemer Madahuri Murali Francisco Grajales Silvia Vital E3 Team

Questions?