US Bridges

Is 55 N over Meramec Rvr

FairPosted for load

Jefferson County, Missouri · S 403 T 43 N R 6 E · Structure no. 442

Built
1964
61 years old, rebuilt 1993
Condition
Fair
inspected June 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
1,425 ft
5 main spans
Daily traffic
55,375
2024 count
Owner
State
State Highway Agency

About this bridge

Is 55 N over Meramec Rvr is a steel continuous stringer/multi-beam or girder carrying Is 55 N over Meramec Rvr in Jefferson County, Missouri. It was built in 1964 and reconstructed in 1993, 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 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 55,375 vehicles a day, roughly 18% of them trucks, projected to reach 102,444 by 2044. The structure is 1,425 ft (434.3 m) long and 76 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

CarriesIs 55 N
CrossesMeramec Rvr
LocationS 403 T 43 N R 6 E
RouteInterstate 55
Coordinates38.45293, -90.37652
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.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
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
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating51.6 US tons
Inventory rating30.8 US tons

Structure

MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans5 (+10 approach)
Design loadHS 20 + Mod
Structure length1,425 ft (434.3 m)
Longest span185 ft (56.4 m)
Deck width76 ft (23.3 m)
Roadway width74 ft (22.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic55,375 (2024)
Projected traffic102,444 by 2044
Trucks18%
Lanes on structure5
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
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—
NavigationNo navigation control on waterway

Frequently asked questions

When was Is 55 N over Meramec Rvr built?

It was built in 1964, making it 61 years old in 2025. It was reconstructed in 1993.

What condition is Is 55 N over Meramec Rvr 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 June 2024.

How much traffic does Is 55 N over Meramec Rvr carry?

About 55,375 vehicles per day (2024 count), of which roughly 18% are trucks.

How long is Is 55 N over Meramec Rvr?

The structure is 1,425 ft (434.3 m) long with a longest span of 185 ft (56.4 m) and a deck 76 ft wide.

Who owns Is 55 N over Meramec Rvr?

It is owned by the State Highway Agency.