Rowell's Covered Bridge

Rowell's Covered Bridge is a covered bridge in West Hopkinton, New Hampshire, which carries Clement Hill Road over the Contoocook River. The Long truss bridge was completed in 1853, and was the third bridge on the site. The bridge is just under 20 feet (6.1 m) wide and 167 feet (51 m) long, and consists of a single span supported by two modified Long trusses resting on granite abutments. The trusses are distinctive in the addition of several arches, which consist of solid timbers that were spliced or butted together, and mortised into other truss members. The bridge's sturdy engineering was demonstrated by the addition of a central pier in the 20th century whose intent was to add strength. The pier, however, acted as a fulcrum, causing the bridge to seesaw under load and weakening its joints. The top of this pier was consequently removed, leaving the bridge largely as designed except for the addition of some metal reinforcing tie rods.

• http://en.wikipedia.org/wiki/Rowell's Covered Bridge