US Bridges

Ruby RD over Cottonwood CR

Poor

Madison County, Montana · Cottonwood CR · Structure no. 010206000000064

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

About this bridge

Ruby RD over Cottonwood CR is a wood or timber stringer/multi-beam or girder carrying Ruby RD over Cottonwood CR 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 poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 50 vehicles a day, projected to reach 75 by 2045. The structure is 30 ft (9.2 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 RD
CrossesCottonwood CR
LocationCottonwood CR
RouteFederal Lands Road 100
CountyMadison County
StateMontana
Coordinates44.90744, -111.99979
Functional classRural Local

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Channel and channel protection4 PoorAdvanced section loss, deterioration, spalling or scour.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating37.8 US tons
Inventory rating29.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans1
Design loadH 20
Structure length30 ft (9.2 m)
Longest span27 ft (8.1 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 RD over Cottonwood CR built?

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

What condition is Ruby RD over Cottonwood CR in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in August 2024.

How much traffic does Ruby RD over Cottonwood CR carry?

About 50 vehicles per day (latest count).

How long is Ruby RD over Cottonwood CR?

The structure is 30 ft (9.2 m) long with a longest span of 27 ft (8.1 m) and a deck 15 ft wide.

Who owns Ruby RD over Cottonwood CR?

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