US Bridges

Il 171 NB First Av over RR - Cn

Fair

Cook County, Illinois · 0.3 M SE I-55 · Structure no. 016048900000000

Built
1963
62 years old, rebuilt 2016
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
166 ft
3 main spans
Daily traffic
39,600
2023 count
Owner
State
State Highway Agency

About this bridge

Il 171 NB First Av over RR - Cn is a steel continuous stringer/multi-beam or girder carrying Il 171 NB First Av over RR - Cn in Cook County, Illinois. It was built in 1963 and reconstructed in 2016, so it is 62 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 39,600 vehicles a day, roughly 9% of them trucks, projected to reach 24,089 by 2046. The structure is 166 ft (50.7 m) long and 56 ft wide.

Location

Open in Google Maps
CarriesIl 171 NB First Av
CrossesRR - Cn
Location0.3 M SE I-55
RouteState Highway 171
CountyCook County
StateIllinois
Coordinates41.79145, -87.81569
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
Deck8 Very GoodNo problems noted.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Last inspectionJune 2023
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 geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating100.8 US tons
Inventory rating59.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length166 ft (50.7 m)
Longest span62 ft (18.8 m)
Deck width56 ft (17.1 m)
Roadway width53 ft (16.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic39,600 (2023)
Projected traffic24,089 by 2046
Trucks9%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesRailroad
Detour if closed—
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 proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Il 171 NB First Av over RR - Cn built?

It was built in 1963, making it 62 years old in 2025. It was reconstructed in 2016.

What condition is Il 171 NB First Av over RR - Cn 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 June 2023.

How much traffic does Il 171 NB First Av over RR - Cn carry?

About 39,600 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is Il 171 NB First Av over RR - Cn?

The structure is 166 ft (50.7 m) long with a longest span of 62 ft (18.8 m) and a deck 56 ft wide.

Who owns Il 171 NB First Av over RR - Cn?

It is owned by the State Highway Agency.