US Bridges

Road 317 over Alkali Creek

FairPosted for load

Petroleum County, Montana · Sect 1 T18N R29E · Structure no. 000061520-00035

Built
1963
62 years old
Condition
Fair
inspected August 2024
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
24 ft
2 main spans
Daily traffic
2
2024 count
Owner
Federal
Bureau of Fish and Wildlife

About this bridge

Road 317 over Alkali Creek is a wood or timber stringer/multi-beam or girder carrying Road 317 over Alkali Creek in Petroleum County, Montana. It was built in 1963, so it is 62 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. Its operating status is: posted for load restriction.

It carries about 2 vehicles a day, projected to reach 2 by 2044. The structure is 24 ft (7.3 m) long and 12 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesRoad 317
CrossesAlkali Creek
LocationSect 1 T18N R29E
RouteFederal Lands Road 0
CountyPetroleum County
StateMontana
Coordinates47.35667, -107.9625
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 protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusPosted for load 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 geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating37 US tons
Inventory rating27 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans2
Design loadUnknown
Structure length24 ft (7.3 m)
Longest span11 ft (3.4 m)
Deck width12 ft (3.7 m)
Roadway width11 ft (3.4 m)
Vertical clearance over deck107 ft (32.7 m)

Traffic and service

Average daily traffic2 (2024)
Projected traffic2 by 2044
Trucks0%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerBureau of Fish and Wildlife
Maintained byBureau of Fish and Wildlife
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$230,000 (4006 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Road 317 over Alkali Creek built?

It was built in 1963, making it 62 years old in 2025.

What condition is Road 317 over Alkali 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 August 2024.

How much traffic does Road 317 over Alkali Creek carry?

About 2 vehicles per day (2024 count).

How long is Road 317 over Alkali Creek?

The structure is 24 ft (7.3 m) long with a longest span of 11 ft (3.4 m) and a deck 12 ft wide.

Who owns Road 317 over Alkali Creek?

It is owned by the Bureau of Fish and Wildlife.