Winding up a foundation contract
- Published: Friday, 08 February 2013 17:37
- Written by CP Staff
Lafarge North America played a key role in last year’s construction of the Blue Creek Wind Farm in Ohio, owned and operated by Iberdrola Renewables. One of the largest wind power plants in the world, with 152 Gamesa G90 turbines, the facility has a generating capacity of 304 MW—enough clean energy to power 76,000 homes.
Lafarge provided Type I portland cement from its Paulding plant to Irving Concrete of Ft. Wayne, Ind., which built a strategically located portable batch plant to produce approximately 122,500 yd. for the project. Construction of 15- to 20-ft. deep concrete foundations to support each of the 328-ft. towers with 2-MW turbines required 30,000 tons of cement.
On average, each of these below-ground support systems used 60 truckloads of concrete (750 yd.), which was poured via a two-step process. A 2-ft.-thick matte was placed first to create a solid base, followed by the casting of an upper pedestal where the tower connects. Huge anchor bolts that fasten to the tower were embedded into this upper section of the concrete. To ensure strength development targets were being attained, concrete quality testing was conducted at 7, 14, 21 and 28 days.
Lafarge also supplied 20,000 tons of Type I cement for soil stabilization of approximately 44 miles of roads, which enabled access to the site under difficult soil conditions and provided a base for permanent roadways. Because the rural roads were not designed to handle the heavy construction traffic loads, they were ground down, mixed with 5 percent cement at a 12-in. treatment depth, and then allowed to harden before being topped with asphalt. This made for a stable base that was engineered to handle the heavy truckloads of concrete and other construction equipment needed to build the wind turbines.
“The rebuilt roadways will require a lot less maintenance in the future due to their stronger and more durable base underneath,” says Lafarge Major Market Manager Tom Rapp. “In what is largely corn and soybean country, the improved, long-lasting roadways are in much better shape now for trucks carrying these agricultural products.”