US Bridges

Is 70 W over Dardenne CR

Fair

St. Charles County, Missouri · S 25 T 47 N R 3 E · Structure no. 6298

Built
1953
72 years old, rebuilt 2002
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
214 ft
3 main spans
Daily traffic
79,535
2024 count
Owner
State
State Highway Agency

About this bridge

Is 70 W over Dardenne CR is a steel continuous stringer/multi-beam or girder carrying Is 70 W over Dardenne CR in St. Charles County, Missouri. It was built in 1953 and reconstructed in 2002, so it is 72 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 79,535 vehicles a day, roughly 12% of them trucks, projected to reach 135,210 by 2044. The structure is 214 ft (65.2 m) long and 79 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

Open in Google Maps
CarriesIs 70 W
CrossesDardenne CR
LocationS 25 T 47 N R 3 E
RouteInterstate 70
CountySt. Charles County
StateMissouri
Coordinates38.80063, -90.64402
Functional classUrban Principal Arterial - Interstate

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating66.5 US tons
Inventory rating39.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length214 ft (65.2 m)
Longest span80 ft (24.4 m)
Deck width79 ft (24.2 m)
Roadway width77 ft (23.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic79,535 (2024)
Projected traffic135,210 by 2044
Trucks12%
Lanes on structure5
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed0.6 mi (1 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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 Is 70 W over Dardenne CR built?

It was built in 1953, making it 72 years old in 2025. It was reconstructed in 2002.

What condition is Is 70 W 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 September 2023.

How much traffic does Is 70 W over Dardenne CR carry?

About 79,535 vehicles per day (2024 count), of which roughly 12% are trucks.

How long is Is 70 W over Dardenne CR?

The structure is 214 ft (65.2 m) long with a longest span of 80 ft (24.4 m) and a deck 79 ft wide.

Who owns Is 70 W over Dardenne CR?

It is owned by the State Highway Agency.