DFI Journal: Vol II November 2008, (DFI)
Effects of Helical Anchor Geometry on Long-Term Performance of Small Wind Tower Foundations Subject to Dynamic Loads
Amy B. Cerato; Rory Victor
The application of this study is to use helical anchors as a foundation system for small wind tower (1 – 10 kW) guyed cables. Helical anchors are currently used to anchor guyed cables of telecommunication and electric towers. However, the increased dynamic vibrations a wind turbine adds to the tower and foundation system under working loads, as well as extreme environmental conditions (e.g., straight line winds, ice load or sudden furling shocks), require additional knowledge about the behavior of helical anchors. These field conditions were simulated in this study by instrumenting a working tower with load cells and 3-axis accelerometers to gather data on wind speed and tower response. These tower responses were then transmitted to the helical anchors through an extensive, large-scale testing program that included monitoring the performance of the helical anchor foundation under dynamic loads, subject to natural variations in both wind regimes, precipitation (water level) and variations in helical anchor geometry. This paper specifically discusses the effects of helical anchor geometry on helical anchor performance under long-term dynamic loads.
|article #1546; publication #1001 (DFIJ-II)|