Design of Wind Turbines - Wind Energy: Renewable Energy and the Environment - page 121

FIGURE 6.20 Placing rebar for pad foundation for 2 MW wind turbine. When finished pad will require
32 metric tons of rebar and 270 m 3 of concrete.
large turbines with tubular towers, foundations are pier, pier with concentric cylinders, or pad on
the ground (Figures 6.20 and 6.21). Piers can be drilled with augers in the appropriate ground, not
solid rocks. The hole for a pier, 5.5 m in diameter and around 9.5 m deep ( Figure 6.22 ) , for a 3 MW
wind turbine was drilled with a giant auger. One advantage of concentric cylinders is less concrete,
as the inner can is backfilled with dirt. Also, the rods can be stressed after the concrete is poured to
obtain a stronger foundation.
FIGURE 6.21 Pad foundation for 2.3 MW wind turbine. Notice the copper wire for grounding.