US Bridges

Il 173 over Boat Channel

Good

Lake County, Illinois · 2.5 M W of Il 59 · Structure no. 049005500000000

Built
1931
94 years old, rebuilt 2011
Condition
Good
inspected September 2021
Type
Stringer/Multi-beam or Girder
Steel
Length
32 ft
1 main span
Daily traffic
11,200
2023 count
Owner
State
State Highway Agency

About this bridge

Il 173 over Boat Channel is a steel stringer/multi-beam or girder carrying Il 173 over Boat Channel in Lake County, Illinois. It was built in 1931 and reconstructed in 2011, 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 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 11,200 vehicles a day, roughly 10% of them trucks, projected to reach 12,726 by 2046. The structure is 32 ft (9.8 m) long and 45 ft wide. If it were closed, the detour would be 19.9 mi (32 km).

Location

Open in Google Maps
CarriesIl 173
CrossesBoat Channel
Location2.5 M W of Il 59
RouteState Highway 173
CountyLake County
StateIllinois
Coordinates42.47191, -88.14693
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.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2021
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating98.2 US tons
Inventory rating68.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length32 ft (9.8 m)
Longest span31 ft (9.4 m)
Deck width45 ft (13.6 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11,200 (2023)
Projected traffic12,726 by 2046
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed19.9 mi (32 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 proposedWidening with deck rehabilitation or replacement
Estimated improvement cost$191,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Il 173 over Boat Channel built?

It was built in 1931, making it 94 years old in 2025. It was reconstructed in 2011.

What condition is Il 173 over Boat Channel 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 September 2021.

How much traffic does Il 173 over Boat Channel carry?

About 11,200 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is Il 173 over Boat Channel?

The structure is 32 ft (9.8 m) long with a longest span of 31 ft (9.4 m) and a deck 45 ft wide.

Who owns Il 173 over Boat Channel?

It is owned by the State Highway Agency.