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Bridges and Structures


A new wood bridge on a forest dirt road, spanning a creek.
New bridge over UM Creek at Black Flat completed August 30, 2018 on the Fishlake National Forest. (USDA Forest Service Photo by Steve Rodriguez)

The Forest Service manages over 6600 road bridges and 7300 trail bridges, ranging from simple structures to complex. These bridges provide critical access links to ensure the public can enjoy more of their public lands and to assist in management of forest lands for resource benefit. Although a great majority of Forest Service bridges were built using timber and engineered wood products, other materials have been used such as steel, concrete and pre-stressed concrete and prefabricated steel structures. The Forest Service, like all road management agencies, is responsible for managing the agency’s network of bridges in accordance with the Federal Highway Administration (FHWA)’s National Bridge Inspection Standards. This ensures that Forest Service bridges are safe for travel by the public.

Some bridges may be posted with a weight restriction less than legal vehicle weights. An overload permit is required to cross a load posted bridge with a vehicle that exceeds the posted weight restrictions. Please contact your local Forest Service office regarding specific questions about overload permits.

People wearing safety gear work on the construction of a new bridge spanning a wide forest creek.
Workers insert a tie rod to help provide stabilization for the new bridge on Road 29 in the Umpqua National Forest’s Tiller Ranger District. The tie rod allows the individual bridge spans to distribute the weight between all the sections and to behave as one complete unit despite being composed of individually cast pieces. (USDA Forest Service photo)

Ropeways and Tramways

A ropeway can be defined as a system for transporting materials or passengers in carriers suspended from or controlled by ropes. Ski lifts, tramways, funiculars, and cable cars are examples of ropeways. Many ski areas and other natural resource based recreation facilities are located on national forests and grasslands and are operated under special use permits. Various types of ropeways are used at these recreation areas to serve sightseers, mountain bikers, and hikers. The permit holders of these recreation areas are responsible for the operation and inspection of these ropeways. The Forest Service provides oversight and monitoring of permittee operations to ensure the public can safely enjoy these activities.

A tram on a snow covered hilltop. A tall evergreen tree with branches covered in snow looms in the foreground.
The tram at Heavenly Mountain Resort on the Lake Tahoe Basin Management Unit, USDA Forest Service. (Photo by Heavenly Mountain Resort)

Tunnels

Some Forest Service lands include tunnels that were built for railroads, vehicle roads, or other purposes. Some of these tunnels are still used for their original purposes and others have been converted to other uses, such as recreational bicycle trails. Tunnels on roads open to the public are subject to the FHWA’s National Tunnel Inspection Standards.

Two hikers walk towards the entrance of an old abandoned railway tunnel in the face of a tree covered hillside. The tunnel is now used as a path for trail hikers.
Hikers use an old railway tunnel on the trails of the Thompson Park area of the Beaverhead-Deerlodge National Forest. (USDA Forest service photo by Preston Keres)

 

https://www.fs.usda.gov/science-technology/infrastructure/bridges-structures