Thursday, January 15, 2015
Crosses and Bends
At around 2 p.m., the bridge workers, Brad and Alex, seriously bundled up, took time to explain to me their mysterious project, underway out of sight, evidenced only by the shadows of narrow scaffolds suspended over the icy river.
The wooden bridge structure on its own will eventually bend in the direction of the river flow, Brad told me, or the other way, because of the sunlight coming from the upstream and southern side. He was not sure which way it would bend, but it would, "like a banana."
The original design addressed that possibility by a single steel cable being woven crossways back and forth underneath the wooden roadbed. Over the 40-plus years of the bridge's life, and perhaps exacerbated by the floods of 1973 and 2011, this cat's cradle construction failed. A picture showed the cables no longer stretching tight from point to point, some parts hanging loose. The sole cable, messed up in one place, necessarily got messed up in others; all was connected.
Brad and Alex have been spending these frigid days removing the old cable and installing separate steel lines for each diagonal traverse of a bridge section, with new fittings and metal plates. The pattern is a series of crosses, succeeding one another across the bottom of the span. Each connection from upstream to downstream and vice versa is a separate line of steel. A problem with one will not automatically be replicated along the bridge.
The Ottauquechee bends in response to the stone it meets. The bridge, it turns out, would like to bend too. Left alone, some day, it will.
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