Page 211 - Fluid Power Engineering

W i nd T urbine Generator (WTG) Components 183

5m

Soil
1.8m Concrete foundation 2.5m
0.4m
17m

FIGURE 9-12 Approximate dimensions of a spread foundation for typical
1.5-MW size turbine.

Deep Foundation
There are different types of deep foundations for wind turbines: Piles,
drilled shaft, caisson, piers, and others. Traditionally, a deep founda-
tion is built on weaker soil by either driving down a solid concrete or
steel beam into the ground or drilling a shaft and pouring concrete.
However, a deep foundation, like the one described below, is used for
normal soil conditions as well. As an illustration, the Patrick and Hen-
derson (P&H) tensionless foundation is described in this section. A
schematic of the foundation is in Fig. 9-13 and an image of a P&H foun-
dation under construction is in Fig. 9-14. Approximate dimensions

FIGURE 9-13 Isometric view of the patented P&H tensionless foundation. For
illustration, the view is cut horizontally and longitudinally. (With permission
from Patrick and Henderson, Inc.)