hwellive@xxxxxxxxxxxx writes:
> For more information:
>
> http://www.columbiapa.org/coveredbridges/38191112.html
>
Nice site, William. Also there's a link to another helpful site- the New
York State Covered Bridge Society which has an explanation that the bridges
were covered to increase the life span of the truss and decking.....
"The open timber truss bridge remained an inexpensive and popular form
for
farm bridges and crossings on minor roads until the early twentieth
century, when it was supplanted by the metal span. The open trusswork was
sometimes sheathed with protective weather boards to preserve the life of
the truss....
"It soon became evident that protecting the bridge's structural system
from the elements would reduce the burden of maintenance and replacement
costs. This protection was most readily achieved by covering the timber
truss bridge with a roof and board sheathing to enclose the frame
structure."
George S.
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