Types

Deck Girder

Deck girder bridges are supported by two or more longitudinal girders (beams). Decks are supported on the tops of the girders and are usually timber (log, sawn or glulam), but may be concrete or steel.

Timber

Log

Typical span 10 to 50 feet

Additional Pictures:

Standard Drawings/Design Aids:
Multiple Log Stringer

Sawn

Typical span 10 to 30 feet

Additional Pictures:

Standard Drawings/Design Aids:
2 x 12 Sawn Lumber Trail Bridge
Solid Sawn Timber Stringer Trail Bridge

Glued Laminated Timber (Glulam)

Typical span 20 to 100 feet

Additional Pictures:

Standard Drawings/Design Aids:
Glued-Laminated Timber Stringer Trail Bridge

Steel

Steel Girder

Typical span 30 to 120 feet

Plank decks are usually nailed to timber nailers bolted to the top of the beams. Glulam decks are usually bolted to brackets that fit under the top flange of the steel beam.

Additional Pictures:

Standard Drawings/Design Aids:
Steel Stringer Trail Bridge