With 20 covered bridges, Lane County has the distinction of possessing
more covered bridges than any other county west of the Mississippi.
Seventeen of these bridges are listed in the National Register of
Historic Places. Covered Bridge Brochure
Covered bridges were constructed to withstand heavy rains and salty sea
air. High-quality timber was more accessible in this area than was more
costly steel and concrete. Covered bridges are similar in design to
steel truss bridges, however, the shortage of steel during World War I
contributed to the need to use wood as bridge building material.
House-type structures over these wooden bridges protect the wood trusses
and floor planking from the elements and more than doubles the life
expectancy of the bridge. As early as 1918, plans for covered bridges
had become standardized to include open windows for light and
ventilation together with such features as laminated floors and interior
whitewashing. The covered bridges still standing represent many hours
of skilled hand labor.