US Bridges

Il 173 over Mokeler Creek

Fair

McHenry County, Illinois · 1.5 M E of US 14 · Structure no. 056005000000000

Built
1930
95 years old, rebuilt 2000
Condition
Fair
inspected May 2023
Type
Slab
Concrete
Length
21 ft
1 main span
Daily traffic
5,350
2023 count
Owner
State
State Highway Agency

About this bridge

Il 173 over Mokeler Creek is a concrete slab carrying Il 173 over Mokeler Creek in McHenry County, Illinois. It was built in 1930 and reconstructed in 2000, so it is 95 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 5,350 vehicles a day, roughly 11% of them trucks, projected to reach 5,880 by 2046. The structure is 21 ft (6.4 m) long and 42 ft wide.

Location

Open in Google Maps
CarriesIl 173
CrossesMokeler Creek
Location1.5 M E of US 14
RouteState Highway 173
CountyMcHenry County
StateIllinois
Coordinates42.43007, -88.57915
Functional classRural Principal Arterial - Other

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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating63.2 US tons
Inventory rating37.8 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length21 ft (6.4 m)
Longest span20 ft (6.1 m)
Deck width42 ft (12.9 m)
Roadway width40 ft (12.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,350 (2023)
Projected traffic5,880 by 2046
Trucks11%
Lanes on structure2
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 173 over Mokeler Creek built?

It was built in 1930, making it 95 years old in 2025. It was reconstructed in 2000.

What condition is Il 173 over Mokeler 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 May 2023.

How much traffic does Il 173 over Mokeler Creek carry?

About 5,350 vehicles per day (2023 count), of which roughly 11% are trucks.

How long is Il 173 over Mokeler Creek?

The structure is 21 ft (6.4 m) long with a longest span of 20 ft (6.1 m) and a deck 42 ft wide.

Who owns Il 173 over Mokeler Creek?

It is owned by the State Highway Agency.