US Bridges

County Highway over I-29/AMENIA Separation

Fair

Cass County, North Dakota · 2 North Harwood Interchg · Structure no. 0029074991

Built
1970
55 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
280 ft
4 main spans
Daily traffic
150
2019 count
Owner
State
State Highway Agency

About this bridge

County Highway over I-29/AMENIA Separation is a steel continuous stringer/multi-beam or girder carrying County Highway over I-29/AMENIA 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 150 vehicles a day, roughly 14% of them trucks, projected to reach 150 by 2039. The structure is 280 ft (85.3 m) long and 32 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesCounty Highway
CrossesI-29/AMENIA Separation
Location2 North Harwood Interchg
RouteCounty Highway 922
CountyCass County
StateNorth Dakota
Coordinates47.00623, -96.9028
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.
Superstructure9 ExcellentNo problems noted.
Substructure7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating51.4 US tons
Inventory rating30.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadH 20
Structure length280 ft (85.3 m)
Longest span101 ft (30.8 m)
Deck width32 ft (9.9 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic150 (2019)
Projected traffic150 by 2039
Trucks14%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.9 mi (3 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 proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost$441,000
NavigationNot applicable (no waterway)

Frequently asked questions

When was County Highway over I-29/AMENIA Separation built?

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

What condition is County Highway over I-29/AMENIA 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 July 2023.

How much traffic does County Highway over I-29/AMENIA Separation carry?

About 150 vehicles per day (2019 count), of which roughly 14% are trucks.

How long is County Highway over I-29/AMENIA Separation?

The structure is 280 ft (85.3 m) long with a longest span of 101 ft (30.8 m) and a deck 32 ft wide.

Who owns County Highway over I-29/AMENIA Separation?

It is owned by the State Highway Agency.