09/06/2002
Constructing A Bridge Of Stone For Greenfields
 A Bridge Of Stone |
We are in the process of building a solid stone bridge across Johnson Mill Creek in Greenfields. The bridge will be composed of eight precision cut slabs of limestone that are 5 feet wide, 10 feet long, 10 inches thick, and weigh approximately 7,000 pounds. These large flat stones will be laid adjacent to each other to create a bridge 10 feet wide and 30 feet long. The end of each pair of flat stones will lay on a perpendicular stone that is rectangular and is 2 feet high by 1 foot wide by 10 feet in length (see engineer’s diagram).
The solid stone slabs of extremely hard limestone were mined approximately three weeks ago from the Cumberland Plateau near Dunlap. These large flat stones are currently in Atlanta being cut precisely to fit our design for the bridge. Because the stones are so hard, it is taking 9 hours to cut each stone.
Last week we poured the foundation for the bridge and it was a formidable task. Two days before the concrete was to arrive, I was at the construction site with the surveyor, the engineer, the contractor, the finish carpenter, and three laborers constructing the concrete forms. The forms had to be precise for the giant slabs of stone to fit perfectly in place. When the concrete arrived it had to be carried from the concrete truck approximately 500 feet down a trail to the creek in the bucket of a Bobcat skidsteer loader on tracks. The concrete then had to be unloaded and spread by shovels. It was a long but successful day.
At the end of the day, we were all discussing how best to move the big stones down to the creek. At one point during our conversion, a thought occurred to me, and I shared it with the men. “You know”, I said, “Several thousand years ago, a group of people were doing almost exactly what we are doing here today. They were standing around looking at a construction site, and discussing how to get big heavy stones from point A to point B. The stones they were talking about though were for the great pyramids of Egypt. Hopefully, our structure will also last a thousand years.
