US Bridges

Mo 21 S over Mill CR

Fair

Ripley County, Missouri · S 8 T 22 N R 2 E · Structure no. 5473

Built
1930
95 years old
Condition
Fair
inspected December 2023
Type
Culvert
Concrete Continuous
Length
22 ft
2 main spans
Daily traffic
883
2024 count
Owner
State
State Highway Agency

About this bridge

Mo 21 S over Mill CR is a concrete continuous culvert carrying Mo 21 S over Mill CR in Ripley County, Missouri. It was built in 1930, so it is 95 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 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 883 vehicles a day, roughly 18% of them trucks, projected to reach 1,325 by 2044. The structure is 22 ft (6.8 m) long and 34 ft wide. If it were closed, the detour would be 31.7 mi (51 km).

Location

Open in Google Maps
CarriesMo 21 S
CrossesMill CR
LocationS 8 T 22 N R 2 E
RouteState Highway 21
CountyRipley County
StateMissouri
Coordinates36.56006, -90.87744
Functional classRural Minor Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating73.4 US tons
Inventory rating43.7 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadH 15
Structure length22 ft (6.8 m)
Longest span10 ft (3 m)
Deck width34 ft (10.4 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic883 (2024)
Projected traffic1,325 by 2044
Trucks18%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed31.7 mi (51 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—
NavigationNo navigation control on waterway

Frequently asked questions

When was Mo 21 S over Mill CR built?

It was built in 1930, making it 95 years old in 2025.

What condition is Mo 21 S over Mill CR 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 December 2023.

How much traffic does Mo 21 S over Mill CR carry?

About 883 vehicles per day (2024 count), of which roughly 18% are trucks.

How long is Mo 21 S over Mill CR?

The structure is 22 ft (6.8 m) long with a longest span of 10 ft (3 m) and a deck 34 ft wide.

Who owns Mo 21 S over Mill CR?

It is owned by the State Highway Agency.