US Bridges

Is 70 W over Is 170

Fair

St. Louis County, Missouri · S 656 T 46 N R 6 E · Structure no. 2577

Built
1979
46 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
290 ft
3 main spans
Daily traffic
60,830
2024 count
Owner
State
State Highway Agency

About this bridge

Is 70 W over Is 170 is a steel continuous stringer/multi-beam or girder carrying Is 70 W over Is 170 in St. Louis County, Missouri. It was built in 1979, so it is 46 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 60,830 vehicles a day, roughly 18% of them trucks, projected to reach 76,038 by 2044. The structure is 290 ft (88.4 m) long and 71 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

Open in Google Maps
CarriesIs 70 W
CrossesIs 170
LocationS 656 T 46 N R 6 E
RouteInterstate 70
CountySt. Louis County
StateMissouri
Coordinates38.7297, -90.33103
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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating68.5 US tons
Inventory rating41.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length290 ft (88.4 m)
Longest span123 ft (37.4 m)
Deck width71 ft (21.6 m)
Roadway width68 ft (20.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic60,830 (2024)
Projected traffic76,038 by 2044
Trucks18%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Is 70 W over Is 170 built?

It was built in 1979, making it 46 years old in 2025.

What condition is Is 70 W over Is 170 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 2024.

How much traffic does Is 70 W over Is 170 carry?

About 60,830 vehicles per day (2024 count), of which roughly 18% are trucks.

How long is Is 70 W over Is 170?

The structure is 290 ft (88.4 m) long with a longest span of 123 ft (37.4 m) and a deck 71 ft wide.

Who owns Is 70 W over Is 170?

It is owned by the State Highway Agency.