US Bridges

172nd Ave SW over Beaver Creek

FairPosted for load

Slope County, North Dakota · SW Outskirts of Marmarth · Structure no. 000000044106240

Built
1955
70 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
200 ft
3 main spans
Daily traffic
200
2018 count
Owner
County
County Highway Agency

About this bridge

172nd Ave SW over Beaver Creek is a steel continuous stringer/multi-beam or girder carrying 172nd Ave SW over Beaver Creek in Slope County, North Dakota. It was built in 1955, so it is 70 years old, older than the North Dakota average of 48.2 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. Its operating status is: posted for load restriction.

It carries about 200 vehicles a day, roughly 10% of them trucks, projected to reach 225 by 2038. The structure is 200 ft (61 m) long and 29 ft wide. If it were closed, the detour would be 47.8 mi (77 km).

Location

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Carries172nd Ave SW
CrossesBeaver Creek
LocationSW Outskirts of Marmarth
RouteCounty Highway 4405
CountySlope County
StateNorth Dakota
Coordinates46.29013, -103.94076
Functional classRural Major Collector

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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating35.6 US tons
Inventory rating21.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadUnknown
Structure length200 ft (61 m)
Longest span76 ft (23.2 m)
Deck width29 ft (8.9 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic200 (2018)
Projected traffic225 by 2038
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed47.8 mi (77 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$477,000
NavigationNo navigation control on waterway

Frequently asked questions

When was 172nd Ave SW over Beaver Creek built?

It was built in 1955, making it 70 years old in 2025.

What condition is 172nd Ave SW over Beaver 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 2023.

How much traffic does 172nd Ave SW over Beaver Creek carry?

About 200 vehicles per day (2018 count), of which roughly 10% are trucks.

How long is 172nd Ave SW over Beaver Creek?

The structure is 200 ft (61 m) long with a longest span of 76 ft (23.2 m) and a deck 29 ft wide.

Who owns 172nd Ave SW over Beaver Creek?

It is owned by the County Highway Agency.