US Bridges

Is 170 E over Or 270

Fair

St. Louis County, Missouri · S 939 T 47 N R 6 E · Structure no. 3161

Built
1978
47 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
251 ft
5 main spans
Daily traffic
10,017
2024 count
Owner
State
State Highway Agency

About this bridge

Is 170 E over Or 270 is a prestressed concrete continuous stringer/multi-beam or girder carrying Is 170 E over Or 270 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 10,017 vehicles a day, roughly 18% of them trucks, projected to reach 12,521 by 2044. The structure is 251 ft (76.4 m) long and 28 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesIs 170 E
CrossesOr 270
LocationS 939 T 47 N R 6 E
RouteInterstate 170
CountySt. Louis County
StateMissouri
Coordinates38.77427, -90.34142
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.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
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 alignment7: Better than present minimum criteria
Operating rating84.3 US tons
Inventory rating35.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans5
Design loadHS 20
Structure length251 ft (76.4 m)
Longest span75 ft (22.8 m)
Deck width28 ft (8.6 m)
Roadway width25 ft (7.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10,017 (2024)
Projected traffic12,521 by 2044
Trucks18%
Lanes on structure1
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed5 mi (8 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$1.8 million (2025 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was Is 170 E over Or 270 built?

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

What condition is Is 170 E over Or 270 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 Or 270 carry?

About 10,017 vehicles per day (2024 count), of which roughly 18% are trucks.

How long is Is 170 E over Or 270?

The structure is 251 ft (76.4 m) long with a longest span of 75 ft (22.8 m) and a deck 28 ft wide.

Who owns Is 170 E over Or 270?

It is owned by the State Highway Agency.