Bridge rails started
Bill Tindall, E.Tn.
This bridge is more than 100 years old which could account for its construction details. As one proceeds across the top of the I-beams half inch plates were added to the top and bottom flange to thicken them toward the middle of the span. So starting at a pier there is one flange stepping up to a total of 4 (2" thick) in the middle of the span and back down again to the next pier.
During my absence the ties were installed without shimming these differences. (The RR "shims" by notching ties) Hence, the ties step up and down like the top flange. The result is an undesirable undulating deck.
As a partial correction it was decided to make the side rail flat. This led to the need to fit each post height to a horizontal "line" between sections of the bridge. But there were further constraints. The material for posts is a 4 x 6 x 8'-1/8" timber, to be cut in half to yield two posts. We had to optimize the layout to achieve the tallest rail we could but not wind up needing to cut so much off the 8' timber that the left over would be uselessly short for a second post. It took most of a day to work out a plan. Having worked out the plan we began railing yesterday and now it begins to look like a trail bridge.
Ten hours on the bridge yesterday lugging 4 x6 x 8 and 2 x 6 x 12 soggy treated lumber and this AM I am a bit stiff.
I have two beds underway for granddaughters but the bridge occupies my "woodworking" for now at this critical stage.
