US Bridges

Il 31 over Mill Creek

Fair

Kane County, Illinois · 1.1 M N of Il 56 · Structure no. 045002000000000

Built
1935
90 years old, rebuilt 2008
Condition
Fair
inspected January 2024
Type
Box Beam or Girders - Multiple
Prestressed Concrete
Length
45 ft
1 main span
Daily traffic
21,500
2023 count
Owner
State
State Highway Agency

About this bridge

Il 31 over Mill Creek is a prestressed concrete box beam or girders - multiple carrying Il 31 over Mill Creek in Kane County, Illinois. It was built in 1935 and reconstructed in 2008, so it is 90 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 21,500 vehicles a day, roughly 5% of them trucks, projected to reach 25,254 by 2046. The structure is 45 ft (13.7 m) long and 54 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesIl 31
CrossesMill Creek
Location1.1 M N of Il 56
RouteState Highway 31
CountyKane County
StateIllinois
Coordinates41.82198, -88.3254
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.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 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 adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating74 US tons
Inventory rating44.3 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length45 ft (13.7 m)
Longest span41 ft (12.4 m)
Deck width54 ft (16.5 m)
Roadway width42 ft (12.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic21,500 (2023)
Projected traffic25,254 by 2046
Trucks5%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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$461,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Il 31 over Mill Creek built?

It was built in 1935, making it 90 years old in 2025. It was reconstructed in 2008.

What condition is Il 31 over Mill 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 January 2024.

How much traffic does Il 31 over Mill Creek carry?

About 21,500 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is Il 31 over Mill Creek?

The structure is 45 ft (13.7 m) long with a longest span of 41 ft (12.4 m) and a deck 54 ft wide.

Who owns Il 31 over Mill Creek?

It is owned by the State Highway Agency.