These photos show the bolt pattern that attaches the base tower section to the foundation for one of the two turbines at Gundersen Health System’s wind project in Cashton, WI. This bolt pattern is critical for the structural integrity of the turbine and transmits the large dynamic forces through the structure to the foundation and soil. The bolt pattern starts with and is integrated into the reinforced steel frame of the foundation. Once the foundation concrete is poured, cured, and backfilled with proper fill, it is ready for tower assembly. To prevent corrosion of the bolts over time it is a good practice to grease the exposed surfaces of the bolts and nuts and fit them with special covers. Corrosion could compromise this joint and possibly lead to a very expensive retrofit involving the foundation. This joint needs to last for the intended duty life of the unit.