US Bridges

RD 1181 over E Fk Big Creek

Fair

Mineral County, Montana · Middle Fk Big CR · Structure no. 011607000000151

Built
1954
71 years old
Condition
Fair
inspected July 2023
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

RD 1181 over E Fk Big Creek is a wood or timber stringer/multi-beam or girder carrying RD 1181 over E Fk Big Creek in Mineral 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 6 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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CarriesRD 1181
CrossesE Fk Big Creek
LocationMiddle Fk Big CR
RouteFederal Lands Road 1181
CountyMineral County
StateMontana
Coordinates47.35824, -115.43204
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating40 US tons
Inventory rating31.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans1
Design loadH 20
Structure length33 ft (10 m)
Longest span31 ft (9.5 m)
Deck width15 ft (4.7 m)
Roadway width14 ft (4.2 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 RD 1181 over E Fk Big Creek built?

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

What condition is RD 1181 over E Fk Big Creek 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 July 2023.

How much traffic does RD 1181 over E Fk Big Creek carry?

About 50 vehicles per day (latest count).

How long is RD 1181 over E Fk Big Creek?

The structure is 33 ft (10 m) long with a longest span of 31 ft (9.5 m) and a deck 15 ft wide.

Who owns RD 1181 over E Fk Big Creek?

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