US Bridges

21st ST SE over I-29/ARTHUR Separation

Fair

Cass County, North Dakota · 4 North of Argusville · Structure no. 0029082709

Built
1970
55 years old
Condition
Fair
inspected April 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
265 ft
4 main spans
Daily traffic
75
2019 count
Owner
State
State Highway Agency

About this bridge

21st ST SE over I-29/ARTHUR Separation is a steel continuous stringer/multi-beam or girder carrying 21st ST SE over I-29/ARTHUR Separation in Cass County, North Dakota. It was built in 1970, so it is 55 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 75 vehicles a day, projected to reach 75 by 2039. The structure is 265 ft (80.8 m) long and 35 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
Carries21st ST SE
CrossesI-29/ARTHUR Separation
Location4 North of Argusville
RouteCounty Highway 914
CountyCass County
StateNorth Dakota
Coordinates47.10833, -96.95826
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionApril 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating68 US tons
Inventory rating40.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadH 20
Structure length265 ft (80.8 m)
Longest span95 ft (29 m)
Deck width35 ft (10.6 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic75 (2019)
Projected traffic75 by 2039
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was 21st ST SE over I-29/ARTHUR Separation built?

It was built in 1970, making it 55 years old in 2025.

What condition is 21st ST SE over I-29/ARTHUR Separation 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 April 2024.

How much traffic does 21st ST SE over I-29/ARTHUR Separation carry?

About 75 vehicles per day (2019 count).

How long is 21st ST SE over I-29/ARTHUR Separation?

The structure is 265 ft (80.8 m) long with a longest span of 95 ft (29 m) and a deck 35 ft wide.

Who owns 21st ST SE over I-29/ARTHUR Separation?

It is owned by the State Highway Agency.