US Bridges

Il 171 (1st Ave) over Des Plaines River

Fair

Cook County, Illinois · 0.7 M N Il 64 · Structure no. 016069700000000

Built
1931
94 years old, rebuilt 1980
Condition
Fair
inspected December 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
194 ft
3 main spans
Daily traffic
20,100
2023 count
Owner
State
State Highway Agency

About this bridge

Il 171 (1st Ave) over Des Plaines River is a prestressed concrete stringer/multi-beam or girder carrying Il 171 (1st Ave) over Des Plaines River in Cook County, Illinois. It was built in 1931 and reconstructed in 1980, so it is 94 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 20,100 vehicles a day, roughly 4% of them trucks, projected to reach 35,754 by 2046. The structure is 194 ft (59 m) long and 63 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesIl 171 (1st Ave)
CrossesDes Plaines River
Location0.7 M N Il 64
RouteState Highway 171
CountyCook County
StateIllinois
Coordinates41.91907, -87.83534
Functional classUrban Other Principal 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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
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 rating82.9 US tons
Inventory rating48.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length194 ft (59 m)
Longest span66 ft (20.1 m)
Deck width63 ft (19.2 m)
Roadway width48 ft (14.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic20,100 (2023)
Projected traffic35,754 by 2046
Trucks4%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemYes

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$2.8 million
NavigationNo navigation control on waterway

Frequently asked questions

When was Il 171 (1st Ave) over Des Plaines River built?

It was built in 1931, making it 94 years old in 2025. It was reconstructed in 1980.

What condition is Il 171 (1st Ave) over Des Plaines River 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 December 2023.

How much traffic does Il 171 (1st Ave) over Des Plaines River carry?

About 20,100 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Il 171 (1st Ave) over Des Plaines River?

The structure is 194 ft (59 m) long with a longest span of 66 ft (20.1 m) and a deck 63 ft wide.

Who owns Il 171 (1st Ave) over Des Plaines River?

It is owned by the State Highway Agency.