US Bridges

69th Ave SW over Knife River

Fair

Mercer County, North Dakota · 1 West 6 South of Zap · Structure no. 000000029112250

Built
1971
54 years old
Condition
Fair
inspected July 2024
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
51 ft
1 main span
Daily traffic
20
2018 count
Owner
County
County Highway Agency

About this bridge

69th Ave SW over Knife River is a prestressed concrete box beam or girders - multiple carrying 69th Ave SW over Knife River in Mercer County, North Dakota. It was built in 1971, so it is 54 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 5 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 20 vehicles a day, projected to reach 20 by 2038. The structure is 51 ft (15.5 m) long and 21 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
Carries69th Ave SW
CrossesKnife River
Location1 West 6 South of Zap
RouteCounty Highway 0
CountyMercer County
StateNorth Dakota
Coordinates47.20224, -101.95467
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
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 adequacy4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating43.9 US tons
Inventory rating22.3 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckOther
Main spans1
Design loadUnknown
Structure length51 ft (15.5 m)
Longest span49 ft (14.9 m)
Deck width21 ft (6.5 m)
Roadway width21 ft (6.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic20 (2018)
Projected traffic20 by 2038
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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 69th Ave SW over Knife River built?

It was built in 1971, making it 54 years old in 2025.

What condition is 69th Ave SW over Knife 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 July 2024.

How much traffic does 69th Ave SW over Knife River carry?

About 20 vehicles per day (2018 count).

How long is 69th Ave SW over Knife River?

The structure is 51 ft (15.5 m) long with a longest span of 49 ft (14.9 m) and a deck 21 ft wide.

Who owns 69th Ave SW over Knife River?

It is owned by the County Highway Agency.