US Bridges

Is 255 N over Is 55 Rp IS270W to IS55

Fair

St. Louis County, Missouri · S 34 T 43 N R 6 E · Structure no. 1013

Built
1964
61 years old, rebuilt 1991
Condition
Fair
inspected July 2024
Type
Box Beam or Girders - Single or Spread
Concrete Continuous
Length
314 ft
5 main spans
Daily traffic
35,885
2024 count
Owner
State
State Highway Agency

About this bridge

Is 255 N over Is 55 Rp IS270W to IS55 is a concrete continuous box beam or girders - single or spread carrying Is 255 N over Is 55 Rp IS270W to IS55 in St. Louis County, Missouri. It was built in 1964 and reconstructed in 1991, so it is 61 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 35,885 vehicles a day, roughly 18% of them trucks, projected to reach 44,856 by 2044. The structure is 314 ft (95.7 m) long and 73 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

Open in Google Maps
CarriesIs 255 N
CrossesIs 55 Rp IS270W to IS55
LocationS 34 T 43 N R 6 E
RouteInterstate 255
CountySt. Louis County
StateMissouri
Coordinates38.50351, -90.33851
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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionJuly 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 rating63.5 US tons
Inventory rating22.8 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans5
Design loadHS 20 + Mod
Structure length314 ft (95.7 m)
Longest span80 ft (24.4 m)
Deck width73 ft (22.1 m)
Roadway width70 ft (21.3 m)
Vertical clearance over deck17 ft (5.3 m)

Traffic and service

Average daily traffic35,885 (2024)
Projected traffic44,856 by 2044
Trucks18%
Lanes on structure5
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 255 N over Is 55 Rp IS270W to IS55 built?

It was built in 1964, making it 61 years old in 2025. It was reconstructed in 1991.

What condition is Is 255 N over Is 55 Rp IS270W to IS55 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 July 2024.

How much traffic does Is 255 N over Is 55 Rp IS270W to IS55 carry?

About 35,885 vehicles per day (2024 count), of which roughly 18% are trucks.

How long is Is 255 N over Is 55 Rp IS270W to IS55?

The structure is 314 ft (95.7 m) long with a longest span of 80 ft (24.4 m) and a deck 73 ft wide.

Who owns Is 255 N over Is 55 Rp IS270W to IS55?

It is owned by the State Highway Agency.