US Bridges

Il 21 (milwaukee) over Des Plaines River

Good

Cook County, Illinois · 0.3 M SE US 45 · Structure no. 016656600000000

Built
2009
16 years old
Condition
Good
inspected November 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
162 ft
3 main spans
Daily traffic
20,400
2023 count
Owner
State
State Highway Agency

About this bridge

Il 21 (milwaukee) over Des Plaines River is a steel continuous stringer/multi-beam or girder carrying Il 21 (milwaukee) over Des Plaines River in Cook County, Illinois. It was built in 2009, so it is 16 years old, younger than the Illinois average of 45.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 20,400 vehicles a day, roughly 3% of them trucks, projected to reach 48,177 by 2046. The structure is 162 ft (49.5 m) long and 85 ft wide.

Location

Open in Google Maps
CarriesIl 21 (milwaukee)
CrossesDes Plaines River
Location0.3 M SE US 45
RouteState Highway 21
CountyCook County
StateIllinois
Coordinates42.10152, -87.88406
Functional classUrban Other Principal Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionNovember 2023
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating89.3 US tons
Inventory rating53.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length162 ft (49.5 m)
Longest span60 ft (18.3 m)
Deck width85 ft (25.9 m)
Roadway width68 ft (20.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic20,400 (2023)
Projected traffic48,177 by 2046
Trucks3%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
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—
NavigationNo navigation control on waterway

Frequently asked questions

When was Il 21 (milwaukee) over Des Plaines River built?

It was built in 2009, making it 16 years old in 2025.

What condition is Il 21 (milwaukee) over Des Plaines River in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in November 2023.

How much traffic does Il 21 (milwaukee) over Des Plaines River carry?

About 20,400 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is Il 21 (milwaukee) over Des Plaines River?

The structure is 162 ft (49.5 m) long with a longest span of 60 ft (18.3 m) and a deck 85 ft wide.

Who owns Il 21 (milwaukee) over Des Plaines River?

It is owned by the State Highway Agency.