US Bridges

Mo 21 S over Palmar CR

Fair

Iron County, Missouri · S 23 T 33 N R 3 E · Structure no. 3580

Built
1985
40 years old
Condition
Fair
inspected October 2023
Type
Culvert
Concrete Continuous
Length
48 ft
3 main spans
Daily traffic
3,513
2024 count
Owner
State
State Highway Agency

About this bridge

Mo 21 S over Palmar CR is a concrete continuous culvert carrying Mo 21 S over Palmar CR in Iron County, Missouri. It was built in 1985, so it is 40 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 3,513 vehicles a day, roughly 18% of them trucks, projected to reach 5,270 by 2044. The structure is 48 ft (14.6 m) long. If it were closed, the detour would be 46 mi (74 km).

Location

Open in Google Maps
CarriesMo 21 S
CrossesPalmar CR
LocationS 23 T 33 N R 3 E
RouteState Highway 21
CountyIron County
StateMissouri
Coordinates37.55008, -90.67941
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 inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating85.3 US tons
Inventory rating51.6 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans3
Design loadHS 20
Structure length48 ft (14.6 m)
Longest span15 ft (4.6 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,513 (2024)
Projected traffic5,270 by 2044
Trucks18%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed46 mi (74 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 Palmar CR built?

It was built in 1985, making it 40 years old in 2025.

What condition is Mo 21 S over Palmar 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 October 2023.

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

About 3,513 vehicles per day (2024 count), of which roughly 18% are trucks.

How long is Mo 21 S over Palmar CR?

The structure is 48 ft (14.6 m) long with a longest span of 15 ft (4.6 m).

Who owns Mo 21 S over Palmar CR?

It is owned by the State Highway Agency.