Foundation System

The Fatigue Resistant Foundation is a proprietary cost- effective foundation design that reduces concrete and rebars quantities and improves the logistics of wind turbine foundation construction.

The proprietary design comprises a plurality of components, namely a central vertical pedestal, a horizontal continuous bottom support slab with a stiffened perimeter, an array of reinforcing ribs extending radially outwardly from the pedestal and a three-dimensional network of vertical, horizontal, diagonal, radial and circumferential post-tensioning elements, embedded in the footing.

The post tensioning elements keep the foundation structure under heavy multi-axial post compression, reduce stress amplitudes and deflections and allow the foundation to have a desirable combination of high stiffness, superior fatigue resistant and durability.

The Fatigue Resistant Foundation improves heat dissipation conditions during construction by having a small ratio of concrete mass to surface area thus eliminating the risk of thermal cracking due to heat of hydration.

Design guidelines and recommendations along with foundation concept validation were provided by top wind energy technology and engineering experts.

The Fatigue Resistant Foundation is available in different design configurations that suits precast concrete construction and offshore wind turbine installations. Some of these configurations are:

• The Partially Prefabricated Foundation System
• The Hybrid Gravity/Rock anchored Foundation System
• The Partially Prefabricated Offshore Foundation System
• The Hybrid Gravity-base/Steel Jacket offshore Foundation System

What are the benefits of the Fatigue Resistant Foundation over the conventional spread footing?

The system provides significant benefits for wind energy developers and foundation contractors. The advantages and benefits include:

• realized savings in construction materials and transportation costs
• improved project logistics by reducing the number of concrete truck loads per footing
• reduced project risk by eliminating thermal cracking due to heat of hydration typically encountered in large concrete pours
• reduced project risk by using prefabricated assemblies thus allowing for construction activities to resume under unfavorable weather conditions
• higher saving ratios for large multi-MW turbine installations and higher hub heights
• reduced volatility due to fluctuation of commodity prices of steel and cement as a result of the reduced material quantities used in construction
• improved design economy for project sites with unfavorable geotechnical conditions and elevated ground water table
• extended foundation lifespan due to the use of multi-axial post tensioning techniques
• simplified tower base leveling method without shimming or use of tower anchor bolts
• novel tower grouting method that allows the application of a continuous grout bed in one grouting session