One of my family members is putting up a tower to support his business radio (farm) , the family GMRS repeater, and a fairly large microwave dish to obtain internet. The choice so far is a Rohn SSV compromised of the following sections: 10NH, 9NH, 8N, 7N, and 6N.
Here the question: The local PE who approved the prints suggested using drilled belled foundations. This nearly doubles the cost of each foundation in terms of drilling and concrete. Typically how much additional resistance to overturning motion do they add above straight sided holes?
