US Bridges

Oberhelman RD over Dardenne CR

Fair

St. Charles County, Missouri · S 20 T 46 N R 1 E · Structure no. 22225

Built
1986
39 years old
Condition
Fair
inspected February 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
35 ft
1 main span
Daily traffic
355
2024 count
Owner
County
County Highway Agency

About this bridge

Oberhelman RD over Dardenne CR is a steel stringer/multi-beam or girder carrying Oberhelman RD over Dardenne CR in St. Charles County, Missouri. It was built in 1986, so it is 39 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 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 355 vehicles a day, roughly 5% of them trucks, projected to reach 781 by 2044. The structure is 35 ft (10.7 m) long and 32 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesOberhelman RD
CrossesDardenne CR
LocationS 20 T 46 N R 1 E
RouteCounty Highway 346
CountySt. Charles County
StateMissouri
Coordinates38.72641, -90.92971
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.
Substructure7 GoodSome minor problems.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionFebruary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourCountermeasures installed to correct a previously existing problem
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating110.1 US tons
Inventory rating79.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadOther
Structure length35 ft (10.7 m)
Longest span33 ft (10.1 m)
Deck width32 ft (9.8 m)
Roadway width30 ft (9.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic355 (2024)
Projected traffic781 by 2044
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 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 Oberhelman RD over Dardenne CR built?

It was built in 1986, making it 39 years old in 2025.

What condition is Oberhelman RD over Dardenne 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 February 2024.

How much traffic does Oberhelman RD over Dardenne CR carry?

About 355 vehicles per day (2024 count), of which roughly 5% are trucks.

How long is Oberhelman RD over Dardenne CR?

The structure is 35 ft (10.7 m) long with a longest span of 33 ft (10.1 m) and a deck 32 ft wide.

Who owns Oberhelman RD over Dardenne CR?

It is owned by the County Highway Agency.