US Bridges

Throop ST over I- 57

Fair

Cook County, Illinois · 1.5 M SW Il 1 · Structure no. 016203200000000

Built
1965
60 years old, rebuilt 2004
Condition
Fair
inspected May 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
263 ft
2 main spans
Daily traffic
950
2022 count
Owner
State
State Highway Agency

About this bridge

Throop ST over I- 57 is a steel continuous stringer/multi-beam or girder carrying Throop ST over I- 57 in Cook County, Illinois. It was built in 1965 and reconstructed in 2004, so it is 60 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 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 950 vehicles a day, roughly 11% of them trucks, projected to reach 1,515 by 2046. The structure is 263 ft (80.3 m) long and 63 ft wide.

Location

Open in Google Maps
CarriesThroop ST
CrossesI- 57
Location1.5 M SW Il 1
RouteCity Street 0
CountyCook County
StateIllinois
Coordinates41.69996, -87.65477
Functional classUrban Local

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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 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 geometry2: Basically intolerable, requiring high priority of replacement
Approach roadway alignment8: Equal to present desirable criteria
Operating rating72.5 US tons
Inventory rating43.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length263 ft (80.3 m)
Longest span136 ft (41.6 m)
Deck width63 ft (19.2 m)
Roadway width46 ft (14 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic950 (2022)
Projected traffic1,515 by 2046
Trucks11%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$3.9 million
NavigationNot applicable (no waterway)

Frequently asked questions

When was Throop ST over I- 57 built?

It was built in 1965, making it 60 years old in 2025. It was reconstructed in 2004.

What condition is Throop ST over I- 57 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 May 2024.

How much traffic does Throop ST over I- 57 carry?

About 950 vehicles per day (2022 count), of which roughly 11% are trucks.

How long is Throop ST over I- 57?

The structure is 263 ft (80.3 m) long with a longest span of 136 ft (41.6 m) and a deck 63 ft wide.

Who owns Throop ST over I- 57?

It is owned by the State Highway Agency.