The Theodore Burr Covered Bridge Society of Pa., Inc. Bridge Terms Page

abutment - the structure that supports the end of the bridge or accepts the thrust of the Burr arch and supports and retains the bridge approach

approach - the road surface leading into the bridge

bolster beam - a timber between the abutement and truss which extends beyond the abutement. Commonly found in Town truss

camber - a built in, upward curve of the bridge

chord - the horizontal members, upper and lower, of a truss system extending from end to end

deck - the surface of the bridge that carries the traffic

floor beam - a transverse member between the trusses that supports the decking and live load

gabion - a galvanized wire box filled with stones used to form retaining walls along
a stream or bridge

parapet - a wall rising above the road level, usually as an upward extension of the wingwall

pier - structure(s) located between the abutements to support a multi-span bridge. Additional support to an existing span. It may be original or added later

portal - the opening at either end of a bridge, the face of that opening

post - a vertical member which is perpendicular or near perpendicular to the bottom chord

runners - lengthwise planks laid over crosswise planks in the tire track area of the bridge deck, probably added sometime after the invention of the automobile to reduce
noise from the loose planks

span - the horizontal distance between two supports of the bridge

trunnel, tree nail - a wooden peg, usually oak, used to fasten timbers in bridge building, sometimes
replaced with galvanized steel bolts

wingwalls - extensions of the abutement which contain the fill of the approach

All Terminology information listed above comes from the book "Pennsylvania's Covered Bridges, A Complete Guide" by Benjamin D. Evans and June R. Evans