US Bridges

County RD SW 366 over Coon CR

Fair

St. Clair County, Missouri · S 18 T 37 N R 26 W · Structure no. 21829

Built
1977
48 years old
Condition
Fair
inspected December 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
323 ft
3 main spans
Daily traffic
100
2023 count
Owner
County
County Highway Agency

About this bridge

County RD SW 366 over Coon CR is a steel continuous stringer/multi-beam or girder carrying County RD SW 366 over Coon CR in St. Clair County, Missouri. It was built in 1977, so it is 48 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 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 100 vehicles a day, roughly 10% of them trucks, projected to reach 120 by 2043. The structure is 323 ft (98.5 m) long and 27 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesCounty RD SW 366
CrossesCoon CR
LocationS 18 T 37 N R 26 W
RouteCounty Highway 325
CountySt. Clair County
StateMissouri
Coordinates37.97606, -93.82639
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating68.5 US tons
Inventory rating25.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 10
Structure length323 ft (98.5 m)
Longest span124 ft (37.8 m)
Deck width27 ft (8.3 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic100 (2023)
Projected traffic120 by 2043
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.8 mi (11 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was County RD SW 366 over Coon CR built?

It was built in 1977, making it 48 years old in 2025.

What condition is County RD SW 366 over Coon 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 SW 366 over Coon CR carry?

About 100 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is County RD SW 366 over Coon CR?

The structure is 323 ft (98.5 m) long with a longest span of 124 ft (37.8 m) and a deck 27 ft wide.

Who owns County RD SW 366 over Coon CR?

It is owned by the County Highway Agency.