US Bridges

Margaret(thorn-Lan over Thorn Creek

Fair

Cook County, Illinois · 1.5 M W Il 394 · Structure no. 016057300000000

Built
1969
56 years old
Condition
Fair
inspected July 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
109 ft
2 main spans
Daily traffic
10,250
2023 count
Owner
State
State Highway Agency

About this bridge

Margaret(thorn-Lan over Thorn Creek is a steel continuous stringer/multi-beam or girder carrying Margaret(thorn-Lan over Thorn Creek in Cook County, Illinois. It was built in 1969, so it is 56 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 10,250 vehicles a day, roughly 8% of them trucks, projected to reach 8,989 by 2046. The structure is 109 ft (33.1 m) long and 60 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesMargaret(thorn-Lan
CrossesThorn Creek
Location1.5 M W Il 394
CountyCook County
StateIllinois
Coordinates41.56821, -87.60821
Functional classUrban Collector

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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating83.9 US tons
Inventory rating50.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length109 ft (33.1 m)
Longest span52 ft (15.8 m)
Deck width60 ft (18.3 m)
Roadway width48 ft (14.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10,250 (2023)
Projected traffic8,989 by 2046
Trucks8%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 km)
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$1.2 million
NavigationNo navigation control on waterway

Frequently asked questions

When was Margaret(thorn-Lan over Thorn Creek built?

It was built in 1969, making it 56 years old in 2025.

What condition is Margaret(thorn-Lan over Thorn 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 2024.

How much traffic does Margaret(thorn-Lan over Thorn Creek carry?

About 10,250 vehicles per day (2023 count), of which roughly 8% are trucks.

How long is Margaret(thorn-Lan over Thorn Creek?

The structure is 109 ft (33.1 m) long with a longest span of 52 ft (15.8 m) and a deck 60 ft wide.

Who owns Margaret(thorn-Lan over Thorn Creek?

It is owned by the State Highway Agency.