Indiana Covered Bridge Terms

(Term definitions are taken from George Gould's 1977 book Indiana Covered Bridges Thru the Years, and all drawings are from Arthur Gatewood's book, Indiana Covered Bridge Location Guide)

 

Arch: timbers cut and fitted to form a symmetrical portion of a circle, attached to posts for added strength: ends rest on abutments below lower chord

 

Brace: a diagonal timber which slopes upward toward the center of the bridge

 

Chord: the horizontal timber or timbers forming part of the truss; lower chord supports the floor, upper chord supports the roof

 

Counter Brace: a diagonal timber or rod which slants upward away from the center of the bridge

 

Deck: the floor or roadbed of the bridge

 

Diagonal: a timber or rod which slants, usually between two panel posts

 

Flared Post: a post with the top slanting toward the end of the bridge

 

Foot Piece: a specially designed casting, usually placed between diagonals and chords for rigid assembly of members

 

Laminated Arch: a series of planks bolted together with staggered joints to form an arch; used in lieu of solid timber

 

Overhang: portion of siding or roof extending beyond span timbers, for added protection; it can be from 0 up to 18 feet

 

Panel: that portion of a truss included between two vertical posts

 

Post: a vertical or upright timber in a truss; wood replaced by iron rods in Howe trusses

 

Span or Clear Span: the length of a bridge between abutments or piers. A truss span is the length between the end posts

 

Truss: an arrangement of timbers and rods to rigidly support each other as well as loads put on the roadway. This requires the use of a suitable combination of triangles ... in short, the truss is the weight bearing support structure of any bridge.