US Bridges

S.Rock Creek Road over Rock Creek

Fair

Gallatin County, Montana · S. of Livingston · Structure no. 011102000000093

Built
1987
38 years old, rebuilt 2005
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
25 ft
1 main span
Daily traffic
50
Owner
Federal
U.S. Forest Service

About this bridge

S.Rock Creek Road over Rock Creek is a wood or timber stringer/multi-beam or girder carrying S.Rock Creek Road over Rock Creek in Gallatin County, Montana. It was built in 1987 and reconstructed in 2005, so it is 38 years old, younger 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 25 ft (7.6 m) long and 16 ft wide. If it were closed, the detour would be 98.2 mi (158 km).

Location

Open in Google Maps
CarriesS.Rock Creek Road
CrossesRock Creek
LocationS. of Livingston
RouteFederal Lands Road 993
CountyGallatin County
StateMontana
Coordinates45.2094, -111.04332
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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating40.7 US tons
Inventory rating31.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans1
Design loadHS 20
Structure length25 ft (7.6 m)
Longest span23 ft (7 m)
Deck width16 ft (4.9 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 S.Rock Creek Road over Rock Creek built?

It was built in 1987, making it 38 years old in 2025. It was reconstructed in 2005.

What condition is S.Rock Creek Road over Rock 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 September 2024.

How much traffic does S.Rock Creek Road over Rock Creek carry?

About 50 vehicles per day (latest count).

How long is S.Rock Creek Road over Rock Creek?

The structure is 25 ft (7.6 m) long with a longest span of 23 ft (7 m) and a deck 16 ft wide.

Who owns S.Rock Creek Road over Rock Creek?

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