US Bridges

Is 70 W over Spencer CR

Fair

St. Charles County, Missouri · S 1799 T 47 N R 4 E · Structure no. 800

Built
1962
63 years old, rebuilt 1995
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
101 ft
3 main spans
Daily traffic
66,614
2024 count
Owner
State
State Highway Agency

About this bridge

Is 70 W over Spencer CR is a steel stringer/multi-beam or girder carrying Is 70 W over Spencer CR in St. Charles County, Missouri. It was built in 1962 and reconstructed in 1995, so it is 63 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 5 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 66,614 vehicles a day, roughly 12% of them trucks, projected to reach 113,244 by 2044. The structure is 101 ft (30.8 m) long and 91 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

Open in Google Maps
CarriesIs 70 W
CrossesSpencer CR
LocationS 1799 T 47 N R 4 E
RouteInterstate 70
CountySt. Charles County
StateMissouri
Coordinates38.79872, -90.60568
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating94.2 US tons
Inventory rating56.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length101 ft (30.8 m)
Longest span34 ft (10.4 m)
Deck width91 ft (27.8 m)
Roadway width89 ft (27 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic66,614 (2024)
Projected traffic113,244 by 2044
Trucks12%
Lanes on structure6
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 Spencer CR built?

It was built in 1962, making it 63 years old in 2025. It was reconstructed in 1995.

What condition is Is 70 W over Spencer 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 Spencer CR carry?

About 66,614 vehicles per day (2024 count), of which roughly 12% are trucks.

How long is Is 70 W over Spencer CR?

The structure is 101 ft (30.8 m) long with a longest span of 34 ft (10.4 m) and a deck 91 ft wide.

Who owns Is 70 W over Spencer CR?

It is owned by the State Highway Agency.