US Bridges

Il 31 over RR - Cn

Fair

Kane County, Illinois · 3.2 M S of US 20 · Structure no. 045001800000000

Built
1955
70 years old, rebuilt 1998
Condition
Fair
inspected January 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
165 ft
3 main spans
Daily traffic
6,250
2023 count
Owner
State
State Highway Agency

About this bridge

Il 31 over RR - Cn is a steel continuous stringer/multi-beam or girder carrying Il 31 over RR - Cn in Kane County, Illinois. It was built in 1955 and reconstructed in 1998, so it is 70 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 6,250 vehicles a day, roughly 4% of them trucks, projected to reach 7,442 by 2046. The structure is 165 ft (50.2 m) long and 43 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesIl 31
CrossesRR - Cn
Location3.2 M S of US 20
RouteState Highway 31
CountyKane County
StateIllinois
Coordinates41.97946, -88.29726
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating101.4 US tons
Inventory rating60.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length165 ft (50.2 m)
Longest span59 ft (18.1 m)
Deck width43 ft (13.2 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,250 (2023)
Projected traffic7,442 by 2046
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesRailroad
Detour if closed9.9 mi (16 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$1.1 million
NavigationNot applicable (no waterway)

Frequently asked questions

When was Il 31 over RR - Cn built?

It was built in 1955, making it 70 years old in 2025. It was reconstructed in 1998.

What condition is Il 31 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 January 2024.

How much traffic does Il 31 over RR - Cn carry?

About 6,250 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Il 31 over RR - Cn?

The structure is 165 ft (50.2 m) long with a longest span of 59 ft (18.1 m) and a deck 43 ft wide.

Who owns Il 31 over RR - Cn?

It is owned by the State Highway Agency.