US Bridges

County Road 371 over Unknown Br

FairClosed to traffic

Carroll County, Missouri · S 28 T 53 N R 21 W · Structure no. 24143

Built
1940
85 years old
Condition
Fair
inspected January 2022
Type
Stringer/Multi-beam or Girder
Steel
Length
28 ft
1 main span
Daily traffic
5
2024 count
Owner
County
County Highway Agency

About this bridge

County Road 371 over Unknown Br is a steel stringer/multi-beam or girder carrying County Road 371 over Unknown Br in Carroll County, Missouri. It was built in 1940, so it is 85 years old, older than the Missouri average of 45.1 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. Its operating status is: closed to all traffic.

It carries about 5 vehicles a day, roughly 10% of them trucks, projected to reach 6 by 2044. The structure is 28 ft (8.5 m) long and 17 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesCounty Road 371
CrossesUnknown Br
LocationS 28 T 53 N R 21 W
RouteCounty Highway 460
CountyCarroll County
StateMissouri
Coordinates39.36997, -93.25989
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJanuary 2022
Inspection intervalevery 24 months
Operating statusClosed to all traffic
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation0: Immediate repair necessary to put back in service
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating0 US tons
Inventory rating0 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadOther
Structure length28 ft (8.5 m)
Longest span28 ft (8.5 m)
Deck width17 ft (5.2 m)
Roadway width17 ft (5.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5 (2024)
Projected traffic6 by 2044
Trucks10%
Lanes on structure1
Traffic directionOne-lane bridge for two-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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$272,000 (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was County Road 371 over Unknown Br built?

It was built in 1940, making it 85 years old in 2025.

What condition is County Road 371 over Unknown Br 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 January 2022.

How much traffic does County Road 371 over Unknown Br carry?

About 5 vehicles per day (2024 count), of which roughly 10% are trucks.

How long is County Road 371 over Unknown Br?

The structure is 28 ft (8.5 m) long with a longest span of 28 ft (8.5 m) and a deck 17 ft wide.

Who owns County Road 371 over Unknown Br?

It is owned by the County Highway Agency.