US Bridges

County RD NE 501 over Big Muddy CR

PoorPosted for load

St. Clair County, Missouri · S 16 T 39 N R 25 W · Structure no. 14661

Built
1950
75 years old
Condition
Poor
inspected December 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
30 ft
2 main spans
Daily traffic
40
2023 count
Owner
County
County Highway Agency

About this bridge

County RD NE 501 over Big Muddy CR is a steel stringer/multi-beam or girder carrying County RD NE 501 over Big Muddy CR in St. Clair County, Missouri. It was built in 1950, so it is 75 years old, older than the Missouri average of 45.1 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 3 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. Its operating status is: posted for load restriction.

It carries about 40 vehicles a day, roughly 10% of them trucks, projected to reach 48 by 2043. The structure is 30 ft (9.1 m) long and 16 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesCounty RD NE 501
CrossesBig Muddy CR
LocationS 16 T 39 N R 25 W
RouteCounty Highway 72
CountySt. Clair County
StateMissouri
Coordinates38.13637, -93.68572
Functional classRural Local

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure3 SeriousLoss of section, deterioration, spalling or scour have seriously affected primary structural components.
Channel and channel protection4 PoorAdvanced section loss, deterioration, spalling or scour.
Last inspectionDecember 2024
Inspection intervalevery 12 months
Operating statusPosted for load restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Deck geometry7: Better than present minimum criteria
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment4: Meets minimum tolerable limits to be left in place as is
Operating rating11.9 US tons
Inventory rating6.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans2
Design loadH 10
Structure length30 ft (9.1 m)
Longest span14 ft (4.3 m)
Deck width16 ft (4.9 m)
Roadway width15 ft (4.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic40 (2023)
Projected traffic48 by 2043
Trucks10%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$289,000 (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was County RD NE 501 over Big Muddy CR built?

It was built in 1950, making it 75 years old in 2025.

What condition is County RD NE 501 over Big Muddy CR in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in December 2024.

How much traffic does County RD NE 501 over Big Muddy CR carry?

About 40 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is County RD NE 501 over Big Muddy CR?

The structure is 30 ft (9.1 m) long with a longest span of 14 ft (4.3 m) and a deck 16 ft wide.

Who owns County RD NE 501 over Big Muddy CR?

It is owned by the County Highway Agency.