US Bridges

55th ST over Flag Creek

Fair

Cook County, Illinois · 2 M W US 45 · Structure no. 016103200000000

Built
1958
67 years old, rebuilt 1992
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
179 ft
3 main spans
Daily traffic
16,600
2022 count
Owner
State
State Highway Agency

About this bridge

55th ST over Flag Creek is a prestressed concrete stringer/multi-beam or girder carrying 55th ST over Flag Creek in Cook County, Illinois. It was built in 1958 and reconstructed in 1992, so it is 67 years old, older than the Illinois average of 45.3 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 16,600 vehicles a day, roughly 4% of them trucks, projected to reach 19,695 by 2046. The structure is 179 ft (54.7 m) long and 70 ft wide.

Location

Open in Google Maps
Carries55th ST
CrossesFlag Creek
Location2 M W US 45
CountyCook County
StateIllinois
Coordinates41.78965, -87.90615
Functional classUrban Minor Arterial

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating82.9 US tons
Inventory rating49.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length179 ft (54.7 m)
Longest span78 ft (23.8 m)
Deck width70 ft (21.3 m)
Roadway width54 ft (16.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic16,600 (2022)
Projected traffic19,695 by 2046
Trucks4%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed—
TollOn a free road
National Highway SystemNo

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 55th ST over Flag Creek built?

It was built in 1958, making it 67 years old in 2025. It was reconstructed in 1992.

What condition is 55th ST over Flag Creek 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 2023.

How much traffic does 55th ST over Flag Creek carry?

About 16,600 vehicles per day (2022 count), of which roughly 4% are trucks.

How long is 55th ST over Flag Creek?

The structure is 179 ft (54.7 m) long with a longest span of 78 ft (23.8 m) and a deck 70 ft wide.

Who owns 55th ST over Flag Creek?

It is owned by the State Highway Agency.