US Bridges

Is 55 S over Rock CR

Good

Jefferson County, Missouri · S 2024 T 42 N R 6 E · Structure no. 12036

Built
2001
24 years old
Condition
Good
inspected November 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
198 ft
3 main spans
Daily traffic
53,723
2024 count
Owner
State
State Highway Agency

About this bridge

Is 55 S over Rock CR is a prestressed concrete continuous stringer/multi-beam or girder carrying Is 55 S over Rock CR in Jefferson County, Missouri. It was built in 2001, so it is 24 years old, younger than the Missouri average of 45.1 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 53,723 vehicles a day, roughly 18% of them trucks, projected to reach 99,388 by 2044. The structure is 198 ft (60.4 m) long and 81 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

CarriesIs 55 S
CrossesRock CR
LocationS 2024 T 42 N R 6 E
RouteInterstate 55
Coordinates38.37467, -90.38019
Functional classUrban Principal Arterial - Interstate

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure8 Very GoodNo problems noted.
Channel and channel protection7 GoodSome minor problems.
Last inspectionNovember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating80.4 US tons
Inventory rating48.6 US tons

Structure

MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 25 or greater
Structure length198 ft (60.4 m)
Longest span75 ft (22.9 m)
Deck width81 ft (24.7 m)
Roadway width78 ft (23.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic53,723 (2024)
Projected traffic99,388 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 S over Rock CR built?

It was built in 2001, making it 24 years old in 2025.

What condition is Is 55 S over Rock CR in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in November 2024.

How much traffic does Is 55 S over Rock CR carry?

About 53,723 vehicles per day (2024 count), of which roughly 18% are trucks.

How long is Is 55 S over Rock CR?

The structure is 198 ft (60.4 m) long with a longest span of 75 ft (22.9 m) and a deck 81 ft wide.

Who owns Is 55 S over Rock CR?

It is owned by the State Highway Agency.