US Bridges

County RD NW 451 over Monegaw CR

FairPosted for load

St. Clair County, Missouri · S 11 T 38 N R 27 W · Structure no. 18947

Built
1930
95 years old
Condition
Fair
inspected December 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
24 ft
1 main span
Daily traffic
20
2023 count
Owner
County
County Highway Agency

About this bridge

County RD NW 451 over Monegaw CR is a steel stringer/multi-beam or girder carrying County RD NW 451 over Monegaw CR in St. Clair 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 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: posted for load restriction.

It carries about 20 vehicles a day, roughly 10% of them trucks, projected to reach 24 by 2043. The structure is 24 ft (7.3 m) long and 13 ft wide. If it were closed, the detour would be 11.8 mi (19 km).

Location

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CarriesCounty RD NW 451
CrossesMonegaw CR
LocationS 11 T 38 N R 27 W
RouteCounty Highway 205
CountySt. Clair County
StateMissouri
Coordinates38.07278, -93.86411
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 inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment6: Equal to present minimum criteria
Operating rating10.9 US tons
Inventory rating6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadOther
Structure length24 ft (7.3 m)
Longest span23 ft (7 m)
Deck width13 ft (4 m)
Roadway width12 ft (3.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic20 (2023)
Projected traffic24 by 2043
Trucks10%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed11.8 mi (19 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$255,000 (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was County RD NW 451 over Monegaw CR built?

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

What condition is County RD NW 451 over Monegaw 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 County RD NW 451 over Monegaw CR carry?

About 20 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is County RD NW 451 over Monegaw CR?

The structure is 24 ft (7.3 m) long with a longest span of 23 ft (7 m) and a deck 13 ft wide.

Who owns County RD NW 451 over Monegaw CR?

It is owned by the County Highway Agency.