US Bridges

121st Ave over Green River

Fair

Billings County, North Dakota · 8 East 12 South Fairfield · Structure no. 000000004129210

Built
1946
79 years old, rebuilt 1975
Condition
Fair
inspected June 2023
Type
Channel Beam
Prestressed Concrete
Length
50 ft
1 main span
Daily traffic
26
2018 count
Owner
County
County Highway Agency

About this bridge

121st Ave over Green River is a prestressed concrete channel beam carrying 121st Ave over Green River in Billings County, North Dakota. It was built in 1946 and reconstructed in 1975, so it is 79 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.

It carries about 26 vehicles a day, projected to reach 26 by 2038. The structure is 50 ft (15.2 m) long and 31 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
Carries121st Ave
CrossesGreen River
Location8 East 12 South Fairfield
RouteCounty Highway 0
CountyBillings County
StateNorth Dakota
Coordinates47.02693, -103.05401
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 protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourCountermeasures installed to correct a previously existing problem
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry7: Better than present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating36 US tons
Inventory rating21.1 US tons

Structure

Structure typeChannel Beam
MaterialPrestressed Concrete
DeckOther
Main spans1
Design loadH 20
Structure length50 ft (15.2 m)
Longest span48 ft (14.6 m)
Deck width31 ft (9.3 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic26 (2018)
Projected traffic26 by 2038
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was 121st Ave over Green River built?

It was built in 1946, making it 79 years old in 2025. It was reconstructed in 1975.

What condition is 121st Ave over Green River 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 June 2023.

How much traffic does 121st Ave over Green River carry?

About 26 vehicles per day (2018 count).

How long is 121st Ave over Green River?

The structure is 50 ft (15.2 m) long with a longest span of 48 ft (14.6 m) and a deck 31 ft wide.

Who owns 121st Ave over Green River?

It is owned by the County Highway Agency.