Towering over 250 feet with a blade length exceeding 150 feet, wind turbines, by virtue of their sheer size and weight, demand a solid foundation on which to stand. When you decide on the type of foundation for a wind turbine, the structure and condition of the soil play big roles in determining the foundation type. Once established, wind turbines dance in the wind, generating electricity for use in businesses and houses.
The most common type of wind turbine foundation, the gravity base provides a great deal of stability. The weight of the concrete base and overlying soil prevents the turbine from tipping over. Resembling an inverted mushroom, the foundation spreads out in a cemented octagon shape with thickness tapering out toward the edges of the platform. The size of the main portion of the octagonal base varies depending on the soil reaction pressure. According to the Southeastern University and College Coalition for Engineering Education, the total reinforcing power of a gravity base ranges from 18144 to 45359 Kilograms. A comparatively inexpensive foundation, the gravity base also goes by the name of spread footing or inverted "T" slab foundation.
Rock-anchored wind turbine foundations work best in areas where bedrock lies within 8 feet of the surface, according to the Southeastern University and College Coalition for Engineering Education. Similar to a gravity base, a rock-anchored foundation utilises a spread-footing foundation that sits on the surface of the soil but includes anchors that extend down through the bedrock and hold a turbine upright.
Another type of rock-anchored foundation requires the placement of piers into the ground to resist the tilting of a wind turbine. Overall, this foundation type is less expensive than the gravity base although it calls for the existence of surface rock formations that can hold anchors in place.
Another typical foundation type, according to Power Naturally, the tube or concrete cylinder foundation supports a wind turbine through a rounded pier resembling a doughnut. Once a proper sized hole has been created--in some cases only about 20 feet across by 40 feet deep--two steel tubes are installed around the perimeter of the hole. Next, pairs of steel poles sit in the space between the steel tubes and are eventually filled with concrete. The centre of the doughnut gets backfilled with dirt, and the whole structure is topped off by a concrete cap.
- 20 of the funniest online reviews ever
- 14 Biggest lies people tell in online dating sites
- Hilarious things Google thinks you're trying to search for
- Southeastern University and College Coalition for Engineering Education: Implications of Consistent LSD/LRFD Implementation in the Design of Wind Turbine Foundations
- AltEnergyMag: In Support of Wind Energy: The Foundations that Underlie Wind Projects
- Power Naturally: Wind Turbine Technology
- Advanced Development Services, Inc: Structural Engineering