US Bridges

Ruby-Centenntial over East Fk Ruby River

Fair

Madison County, Montana · East Fk Ruby River · Structure no. 010206000000030

Built
1954
71 years old
Condition
Fair
inspected August 2024
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
33 ft
1 main span
Daily traffic
50
Owner
Federal
U.S. Forest Service

About this bridge

Ruby-Centenntial over East Fk Ruby River is a wood or timber stringer/multi-beam or girder carrying Ruby-Centenntial over East Fk Ruby River in Madison County, Montana. It was built in 1954, so it is 71 years old, older than the Montana average of 47 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 50 vehicles a day, projected to reach 75 by 2045. The structure is 33 ft (10 m) long and 15 ft wide. If it were closed, the detour would be 98.2 mi (158 km).

Location

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CarriesRuby-Centenntial
CrossesEast Fk Ruby River
LocationEast Fk Ruby River
RouteFederal Lands Road 100
CountyMadison County
StateMontana
Coordinates44.77877, -112.01941
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating28.5 US tons
Inventory rating22.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans1
Design loadHS 20
Structure length33 ft (10 m)
Longest span31 ft (9.4 m)
Deck width15 ft (4.7 m)
Roadway width14 ft (4.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic50 (—)
Projected traffic75 by 2045
Trucks—
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.2 mi (158 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerU.S. Forest Service
Maintained byU.S. Forest Service
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Ruby-Centenntial over East Fk Ruby River built?

It was built in 1954, making it 71 years old in 2025.

What condition is Ruby-Centenntial over East Fk Ruby River in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in August 2024.

How much traffic does Ruby-Centenntial over East Fk Ruby River carry?

About 50 vehicles per day (latest count).

How long is Ruby-Centenntial over East Fk Ruby River?

The structure is 33 ft (10 m) long with a longest span of 31 ft (9.4 m) and a deck 15 ft wide.

Who owns Ruby-Centenntial over East Fk Ruby River?

It is owned by the U.S. Forest Service.