A brief introduction to Offshore wind turbine, problems associated,difference from other foundation, types used, basic theory, and design loads.

1. IMPORTANCE OF FOUNDATION DESIGN
• HIGH COST OF THE FOUNDATION ( NEARLY 25%-35% OF OVERALL COST )
• NATURAL FREQUENCIES OF THESE STRUCTURES ARE VERY CLOSE TO THE
FORCING FREQUENCIES OF THE WIND, WAVE, ROTOR FREQUENCY AND BLADE
SHADOW FREQUENCY.

2. FOUNDATION DIFFERENCES
OIL & GAS PLATFORM VS WIND
TURBINES
RELATIVELY STIFF RELATIVELY FLEXIBLE
STRUCTURAL DYNAMICS NOT CRITICAL STRUCTURAL DYNAMICS VERY
CRITICAL
WAVE LOAD DOMINANT WAVE AND WIND LOAD BOTH
IMPORTANT
STRAIGHT FORWARD RELATION FORCE-RESPONSE COMPLEX, UNCORRELATED
LOADING
‘PROTOTYPE’ GENERALLY LARGE NUMBERS

3. DESIGN CRITERIA & CONSIDERATIONS
• LOADS: MAGNITUDE OF THE PERMANENT LOAD OF THE PLATFORM
WIND / WAVE / CURRENT
RATIO VERTICAL / HORIZONTAL LOADS
QUASI STATIC / CYCLIC
• WATER DEPTH
• SEA FLOOR
SOIL TYPE
CURRENT -> SCOURING
• FABRICATION, TRANSPORTATION & INSTALLATION
AVAILABLE CONSTRUCTION SITES / EQUIPMENT

4. GRAVITY FOUNDATIONS
• LOADING SITUATION VERY DIFFERENT FROM PILED FOUNDATION
• SUBSTANTIAL VERTICAL LOADING REQUIRED ( STABILITY)
• GENERALLY IMPRACTICAL SUPPORT STRUCTURE FOR WIND
TURBINES IN RELATIVELY SHALLOW WATER

5. PILED FOUNDATIONS
• FLEXIBILITY / ADAPTABILITY :
SOIL CONDITIONS
WATER DEPTH
SCOUR
DIAMETER AND WALL THICKNESS
TENSION & COMPRESSION
PENETRATION AND NUMBER
TRACK RECORD / EXPERIENCE
DIFFERENT INSTALLATION METHODS

6. CHOICE OF FOUNDATION TYPE
• LOADS WIND / WAVE / CURRENT
HORIZONTAL AND VERTICAL
QUASI STATIC / CYCLIC
• WATER DEPTH
• SOIL CONDITIONS
• STORAGE REQUIREMENTS
• TRANSPORTATION / INSTALLATION EQUIPMENT REQUIREMENTS
• AVAILABLE CONSTRUCTION SITES / EQUIPMENT
• ECONOMICS

7. THINK ABOUT ????????

9. CURRENT & FUTURE PROTOTYPES
• CURRENT FOUNDATION TYPES
INCLUDES FOUNDATIONS CURRENTLY AVAILABLE TO OFFSHORE WIND
DEVELOPERS
• FUTURE PROTOTYPES
INCLUDES FLOATING AND DEEPWATER CONCEPTS

10. FOUNDATIONS USED ON UTILITY-SCALE
OFFSHORE WIND PROJECTS TODAY:
•Mono pile
•Gravity foundation
•Tripod foundation

11. FLOATING CONCEPTS:
WHILE SEVERAL FLOATING OFFSHORE WIND CONCEPTS EXIST, TWO DESIGNS ARE
THE BEST KNOWN:
• HYWIND
• WINDFLOAT

12. HYWIND WINDFLOAT

13. ANALYSIS TO BE DONE :
Preliminary
Sizing
Stability
Load Case
Structural
Design

14. DESIGN LOAD CASES:
• POWER PRODUCTION FAULT
• PARKED FAULT
• ADDITIONAL CASES
• ULTIMATE STRENGTH LOAD CONVERGENCE
• FATIGUE LOAD CONVERGENCE

15. DESIGN IN SHORT

16. THANK YOU