Contributed by Virginia Lawrence
Yesterday I walked down to the Covered Bridge in the early morning where I spoke with the Supervisor, Joe Boris, who explained that in the next two or three days the construction team was going to remove some shims, and that something (?) would be lowered by about 3 inches.
When I got home, I realized I didn’t really understand what was going to happen, so I went back to find out more. During the course of three more trips to the covered bridge the Boris brothers, Supervisor Joe and Master Carpenter John, explained the bridge rehabilitation project in a very clear way.
John said that the bridge was constructed with a slight arch from end to end known as a camber. He illustrated this concept by lacing his fingers together palms down. When the bridge is resting on the two foundations at either end the weight of the bridge pushes down (he pushed his hands down), the trusses tighten, and the whole structure becomes rigid.
The diagonal lattice pieces were held together with wooden dowels, “trunnels” or “treenails.” In order to replace the damaged timbers it would be necessary to remove the trunnels. However, the camber of the wooden bridge would first need to be loosened by raising the wooden bridge off its foundations. Again, John illustrated with his hands.
Here is where the Acrow bridge came in. An Acrow bridge, made of steel trusses, was assembled inside the wooden bridge. It rested on the new stone ramp at one end and on Ragin road at the other Once in place, it was raised with shims (small wedges) so that the wooden bridge was lifted off its foundations by about three inches. With the wooden bridge hanging in place, supported by the Acrow bridge, the structure was no longer rigid. The trunnels could be removed and the timbers replaced.
In the next few days (July 19-22) the shims under the Acrow bridge will be removed, the Acrow bridge will be lowered about 3 inches, the wooden bridge will settle back onto its foundations, and lattices and trunnels will be tight again. Joe told me the difference will not be visible.
The Acrow bridge is due to be removed sometime in August, and that will be easy to see.
John Boris says that he’s worked all over the place in the State of New York, but that this specific location is his favorite. He has seen eagles flying over and trout jumping out of the river. He loves being here because of the site’s peacefulness and beauty.