US Bridges

Is 170 E over Cst Frost Ave

Fair

St. Louis County, Missouri · S 2 T 46 N R 6 E · Structure no. 2561

Built
1978
47 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
165 ft
3 main spans
Daily traffic
27,257
2024 count
Owner
State
State Highway Agency

About this bridge

Is 170 E over Cst Frost Ave is a steel stringer/multi-beam or girder carrying Is 170 E over Cst Frost Ave in St. Louis County, Missouri. It was built in 1978, so it is 47 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 27,257 vehicles a day, roughly 12% of them trucks, projected to reach 34,071 by 2044. The structure is 165 ft (50.3 m) long and 42 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

Open in Google Maps
CarriesIs 170 E
CrossesCst Frost Ave
LocationS 2 T 46 N R 6 E
RouteInterstate 170
CountySt. Louis County
StateMissouri
Coordinates38.76283, -90.33876
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Approach roadway alignment8: Equal to present desirable criteria
Operating rating75.4 US tons
Inventory rating45.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length165 ft (50.3 m)
Longest span91 ft (27.7 m)
Deck width42 ft (12.9 m)
Roadway width39 ft (12 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic27,257 (2024)
Projected traffic34,071 by 2044
Trucks12%
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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$1.6 million (2025 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was Is 170 E over Cst Frost Ave built?

It was built in 1978, making it 47 years old in 2025.

What condition is Is 170 E over Cst Frost Ave 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 170 E over Cst Frost Ave carry?

About 27,257 vehicles per day (2024 count), of which roughly 12% are trucks.

How long is Is 170 E over Cst Frost Ave?

The structure is 165 ft (50.3 m) long with a longest span of 91 ft (27.7 m) and a deck 42 ft wide.

Who owns Is 170 E over Cst Frost Ave?

It is owned by the State Highway Agency.