Kumar & Associates, Inc. conducted geotechnical engineering studies for the Vestas Blade and Nacelle Campus located at the intersection of County Road 27 and County Road 6 in Weld County, Colorado. The facility located on 177 acres of undeveloped land consisted of approximately 450,000 square feet for various size steel framed buildings associated with the Blade manufacturing operations. An additional 250,000 square foot building was constructed for the Nacelle manufacturing operations.

Site grading for the facility consisted of 10 feet or less of cut and fill to achieve the design grades. The off-site work included approximately 2.5 miles of water and sanitary sewer line constructed to serve the site, as well as approximately 1 mile of County roadway improvements. An approximate 30 acre gravel surfaced blade storage yard to be accessed by heavy fork lift traffic was also planned. The studies included drilling exploratory borings, conducting laboratory testing, and engineering analysis. Variable swell and consolidation characteristics of the soil required recommendations for over-excavation and replacement of a portion of the surface soils below slabs and foundations. The foundation system for the buildings consisted of conventional spread footings placed on non-expansive, engineered fill.

Recommendations were presented that allowed reuse of on-site soils in all applications, reducing the requirements for extensive import of soils. Recommended pavement sections were developed for rigid and flexible pavements and the gravel surfaced storage yard. Due to the high wheel loads, special paving and subgrade preparation considerations were required. The use of subgrade geogrid reinforcement was recommended to reduce the thickness of surface treatments. In addition to the geotechnical engineering studies, we also sampled surface soils for testing to evaluate the potential for surface contamination due to past site usage. Testing concentrated on evaluating for contaminants normally associated with agricultural activities.

Finally, a pre-demolition survey was performed on existing buildings associated with a previous farm to identify potential presence of asbestos and lead based paint. A limited subsurface drilling program was also performed to evaluate the potential for leakage of on-site petroleum storage tanks.