Two of these have 9 sides, one has 11. The ramps and ladders were part of how the silos were filled: the grain or silage was conveyed to the top and poured down into the silo, while workers tramped and spread the silage around to distribute it evenly. Apparently some farmers would do this all day, but the usual practice was to do four hours of this and then you would get to handle the chute. The ramps and ladders were both to enter and exit the silos. Many silos didn't even have this escape path!
Pioneer Town Museum, Cedaredge, CO