US Bridges

Is 255 N over Mississippi Rvr UP RR

Fair

St. Louis County, Missouri · S 6 T 43 N R 7 E · Structure no. 1541

Built
1985
40 years old
Condition
Fair
inspected November 2023
Type
Arch - Thru
Steel
Length
4,004 ft
1 main span
Daily traffic
30,251
2024 count
Owner
State
State Highway Agency

About this bridge

Is 255 N over Mississippi Rvr UP RR is a steel arch - thru carrying Is 255 N over Mississippi Rvr UP RR in St. Louis County, Missouri. It was built in 1985, so it is 40 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 30,251 vehicles a day, roughly 18% of them trucks, projected to reach 37,814 by 2044. The structure is 4,004 ft (1,220.3 m) long and 54 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

Open in Google Maps
CarriesIs 255 N
CrossesMississippi Rvr UP RR
LocationS 6 T 43 N R 7 E
RouteInterstate 255
CountySt. Louis County
StateMissouri
Coordinates38.48734, -90.27695
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.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating69.4 US tons
Inventory rating41.7 US tons

Structure

Structure typeArch - Thru
MaterialSteel
DeckConcrete, cast-in-place
Main spans1 (+14 approach)
Design loadHS 20
Structure length4,004 ft (1,220.3 m)
Longest span910 ft (277.4 m)
Deck width54 ft (16.5 m)
Roadway width51 ft (15.5 m)
Vertical clearance over deck20 ft (6.1 m)

Traffic and service

Average daily traffic30,251 (2024)
Projected traffic37,814 by 2044
Trucks18%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesRailroad and waterway
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—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was Is 255 N over Mississippi Rvr UP RR built?

It was built in 1985, making it 40 years old in 2025.

What condition is Is 255 N over Mississippi Rvr UP RR 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 November 2023.

How much traffic does Is 255 N over Mississippi Rvr UP RR carry?

About 30,251 vehicles per day (2024 count), of which roughly 18% are trucks.

How long is Is 255 N over Mississippi Rvr UP RR?

The structure is 4,004 ft (1,220.3 m) long with a longest span of 910 ft (277.4 m) and a deck 54 ft wide.

Who owns Is 255 N over Mississippi Rvr UP RR?

It is owned by the State Highway Agency.