US Bridges

Mo 21 S over Cotter CR

Fair

Jefferson County, Missouri · S 22 T 40 N R 4 W · Structure no. 3612

Built
1989
36 years old
Condition
Fair
inspected December 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
199 ft
3 main spans
Daily traffic
13,304
2024 count
Owner
State
State Highway Agency

About this bridge

Mo 21 S over Cotter CR is a prestressed concrete stringer/multi-beam or girder carrying Mo 21 S over Cotter CR in Jefferson County, Missouri. It was built in 1989, so it is 36 years old, younger 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 13,304 vehicles a day, roughly 7% of them trucks, projected to reach 24,612 by 2044. The structure is 199 ft (60.7 m) long and 41 ft wide. If it were closed, the detour would be 24.2 mi (39 km).

Location

Open in Google Maps
CarriesMo 21 S
CrossesCotter CR
LocationS 22 T 40 N R 4 W
RouteState Highway 21
CountyJefferson County
StateMissouri
Coordinates38.18355, -90.56142
Functional classRural Principal Arterial - Other

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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionDecember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating63.5 US tons
Inventory rating37.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length199 ft (60.7 m)
Longest span67 ft (20.3 m)
Deck width41 ft (12.6 m)
Roadway width39 ft (11.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,304 (2024)
Projected traffic24,612 by 2044
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed24.2 mi (39 km)
TollOn a free road
National Highway SystemYes

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 Cotter CR built?

It was built in 1989, making it 36 years old in 2025.

What condition is Mo 21 S over Cotter 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 2024.

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

About 13,304 vehicles per day (2024 count), of which roughly 7% are trucks.

How long is Mo 21 S over Cotter CR?

The structure is 199 ft (60.7 m) long with a longest span of 67 ft (20.3 m) and a deck 41 ft wide.

Who owns Mo 21 S over Cotter CR?

It is owned by the State Highway Agency.