US Bridges

County RD 6420 over Spring CR

Fair

Howell County, Missouri · S 29 T 24 N R 9 W · Structure no. 23800

Built
1940
85 years old
Condition
Fair
inspected November 2024
Type
Slab
Concrete
Length
91 ft
9 main spans
Daily traffic
50
2023 count
Owner
County
County Highway Agency

About this bridge

County RD 6420 over Spring CR is a concrete slab carrying County RD 6420 over Spring CR in Howell 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.

It carries about 50 vehicles a day, roughly 10% of them trucks, projected to reach 65 by 2043. The structure is 91 ft (27.7 m) long and 22 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

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CarriesCounty RD 6420
CrossesSpring CR
LocationS 29 T 24 N R 9 W
RouteCounty Highway 433
CountyHowell County
StateMissouri
Coordinates36.7159, -91.98208
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
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 inspectionNovember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
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 adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating54.6 US tons
Inventory rating17.9 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans9
Design loadOther
Structure length91 ft (27.7 m)
Longest span10 ft (3 m)
Deck width22 ft (6.7 m)
Roadway width22 ft (6.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic50 (2023)
Projected traffic65 by 2043
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was County RD 6420 over Spring CR built?

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

What condition is County RD 6420 over Spring 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 November 2024.

How much traffic does County RD 6420 over Spring CR carry?

About 50 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is County RD 6420 over Spring CR?

The structure is 91 ft (27.7 m) long with a longest span of 10 ft (3 m) and a deck 22 ft wide.

Who owns County RD 6420 over Spring CR?

It is owned by the County Highway Agency.