SBIR Phase I: Phase I Research: Beam/Hub Connection Design - Considerations for Wind Energy Industry loadings for A Precast Footer Assembly

Rute Foundations, Portland OR

Investigators

Abstract

This Small Business Innovation Research Phase I project supports research into the structural engineering of a modular foundation for large wind energy towers. Structural connections using assembled components have never been contemplated in cases where the forces involved are of the magnitude currently experienced in today's wind turbines. About 3,000 turbines (and foundations) are constructed each year in the U.S. and about 10,000 internationally, representing a $1 billion domestic market. This market is served well today by cast-in-place concrete technology. Nevertheless a lighter, stronger, and quicker-to-install foundation system would introduce tremendous value to the entire wind energy industry. First, it would improve project economics and reduce the price of clean wind electricity. Second, the innovation would eliminate financing and project timing issues inherent with current concrete works. Third, the innovation would allow farmland to be fully recovered at the end of the project lifecycle, as the proposed structural elements are designed to be lifted back out of the earth, re-tested for strength, and then reused. Fourth, the new approach will eliminate 5,000 tons of carbon dioxide emissions for each 100 megawatt wind farm, based on a reduction in the required cement for the incumbent cast-in-place technology. The intellectual merit of this project consists in advanced materials research, advanced structural engineering research, advanced construction methods research, and combining the three into a structural element that can meet the massive overturning forces required of a wind turbine foundation. The research will include finite element modeling of structural design discoveries, plus new research into post-tensioning concrete systems, and new analytical methods in foundation study. The results of the research program are intended to yield a commercially viable structural element that can connect the tower to the girder elements safely, efficiently, and cost-effectively, based on the scale and requirements of the wind industry.