US Bridges

Natural Bridge RD over Cowmire CR

FairPosted for load

St. Louis County, Missouri · S 131 T 46 N R 5 E · Structure no. 34910

Built
1984
41 years old
Condition
Fair
inspected November 2023
Type
Culvert
Concrete
Length
41 ft
3 main spans
Daily traffic
7,228
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Natural Bridge RD over Cowmire CR is a concrete culvert carrying Natural Bridge RD over Cowmire CR in St. Louis County, Missouri. It was built in 1984, so it is 41 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 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 7,228 vehicles a day, roughly 5% of them trucks, projected to reach 9,758 by 2043. The structure is 41 ft (12.6 m) long and 49 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesNatural Bridge RD
CrossesCowmire CR
LocationS 131 T 46 N R 5 E
RouteCity Street 0
CountySt. Louis County
StateMissouri
Coordinates38.75681, -90.42922
Functional classUrban 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 protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating30.8 US tons
Inventory rating18.8 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length41 ft (12.6 m)
Longest span13 ft (4 m)
Deck width49 ft (14.8 m)
Roadway width47 ft (14.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,228 (2023)
Projected traffic9,758 by 2043
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal 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 Natural Bridge RD over Cowmire CR built?

It was built in 1984, making it 41 years old in 2025.

What condition is Natural Bridge RD over Cowmire 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 2023.

How much traffic does Natural Bridge RD over Cowmire CR carry?

About 7,228 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is Natural Bridge RD over Cowmire CR?

The structure is 41 ft (12.6 m) long with a longest span of 13 ft (4 m) and a deck 49 ft wide.

Who owns Natural Bridge RD over Cowmire CR?

It is owned by the City or Municipal Highway Agency.