US Bridges

Is 170 W over Is 270 Rp Dunn RD to Is

Fair

St. Louis County, Missouri · S 939 T 47 N R 6 E · Structure no. 29143

Built
2002
23 years old
Condition
Fair
inspected December 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
1,558 ft
4 main spans
Daily traffic
27,257
2024 count
Owner
State
State Highway Agency

About this bridge

Is 170 W over Is 270 Rp Dunn RD to Is is a steel continuous stringer/multi-beam or girder carrying Is 170 W over Is 270 Rp Dunn RD to Is in St. Louis County, Missouri. It was built in 2002, so it is 23 years old, younger 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 18% of them trucks, projected to reach 34,071 by 2044. The structure is 1,558 ft (474.9 m) long and 31 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesIs 170 W
CrossesIs 270 Rp Dunn RD to Is
LocationS 939 T 47 N R 6 E
RouteInterstate 170
CountySt. Louis County
StateMissouri
Coordinates38.77546, -90.34074
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.
Substructure7 GoodSome minor problems.
Last inspectionDecember 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 geometry4: Meets minimum tolerable limits to be left in place as is
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 spans4 (+11 approach)
Design loadHS 25 or greater
Structure length1,558 ft (474.9 m)
Longest span183 ft (55.9 m)
Deck width31 ft (9.3 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deck17 ft (5.3 m)

Traffic and service

Average daily traffic27,257 (2024)
Projected traffic34,071 by 2044
Trucks18%
Lanes on structure1
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 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 170 W over Is 270 Rp Dunn RD to Is built?

It was built in 2002, making it 23 years old in 2025.

What condition is Is 170 W over Is 270 Rp Dunn RD to Is 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 December 2024.

How much traffic does Is 170 W over Is 270 Rp Dunn RD to Is carry?

About 27,257 vehicles per day (2024 count), of which roughly 18% are trucks.

How long is Is 170 W over Is 270 Rp Dunn RD to Is?

The structure is 1,558 ft (474.9 m) long with a longest span of 183 ft (55.9 m) and a deck 31 ft wide.

Who owns Is 170 W over Is 270 Rp Dunn RD to Is?

It is owned by the State Highway Agency.