Timber bridge
Beam bridge | |
---|---|
Characteristics | |
Material | Wood |
A timber bridge or wooden bridge is a
History
The most ancient form of timber bridge is the log bridge, created by felling a tree over a gap needing to be crossed.[citation needed]
Among the oldest timber bridges is the
Environment
Recently timber bridges have received attention in the United States because they are environmentally friendly compared to other bridge types. Until 1991, the Federal Highway Administration has concentrated on major highways and other primary roads; rural highways and local roads, where timber bridges are mostly found, have received less attention.
Local and state agencies prefer timber bridges because timber is a
Covered bridges, usually made of wood and enclosed as if a tunnel, were very popular in the 19th century in the US. Today, timber bridges are promoted as environmentally friendly, and as a way to protect water quality and the habitat along waterways. Timber bridges can be placed over small streams or channels with firm, stable banks.[3]
The passing of TBI and ISTEA by the US Congress has provided an impetus to identify and develop standard designs for timber bridges, which the
Examples
The University of Minnesota Extension Service recommends three types of timber bridges for wilderness lands, and suggest that a licensed engineer be hired to insure the bridge design is safe and appropriate for the site. Using fallen trees,
Personnel from Virginia Tech have described in detail how to build a stringer bridge using standard bridge design procedures, for example, by placing timber stringers across the abutment, using a bent to support a trestle or timber frame. Their methods are quick and cost little.[5]
References
- ^ a b Wacker, James P.; Smith, Matthew S. (2001). "Standard plans for timber bridge superstructures". Forest Products Laboratory. Madison: Department of Agriculture, Forest Service. p. 53.
- ^ Sheila Rimal Duwadi; Robert C. Wood. "The Federal Highway Administration Timber Bridge Program" (PDF). Retrieved April 28, 2012.
- ^ a b "Timber Bridges". University of Minnesota. 2002. Archived from the original on March 18, 2012. Retrieved April 24, 2012.
- ^ James Wacher; Mathew Smith. "Standard Plans for Timber Bridge Structures" (PDF). Forest Products Laboratory. Retrieved April 24, 2012.
- ^ "Timber Stringer Bridge". Virginia Tech. Retrieved April 24, 2012.
External links
- Media related to Wooden bridges at Wikimedia Commons
- Timber Bridge Economics
- Types of Timber Bridges
- Video on building Chinese wooden bridges by UNESCO
- Vehicular, Pedestrian, Covered, Golf Cart, Boardwalks: Timber Bridge Gallery