US Bridges

I-39 Sb/Us 51 SB over Tomahawk Creek

Fair

LaSalle County, Illinois · 3.5 MI N of I-80 · Structure no. 050017300000000

Built
1979
46 years old
Condition
Fair
inspected November 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
136 ft
2 main spans
Daily traffic
9,300
2023 count
Owner
State
State Highway Agency

About this bridge

I-39 Sb/Us 51 SB over Tomahawk Creek is a prestressed concrete stringer/multi-beam or girder carrying I-39 Sb/Us 51 SB over Tomahawk Creek in LaSalle County, Illinois. It was built in 1979, so it is 46 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 9,300 vehicles a day, roughly 44% of them trucks, projected to reach 9,141 by 2046. The structure is 136 ft (41.5 m) long and 42 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI-39 Sb/Us 51 SB
CrossesTomahawk Creek
Location3.5 MI N of I-80
RouteInterstate 39
CountyLaSalle County
StateIllinois
Coordinates41.41936, -89.05849
Functional classRural Principal Arterial - Interstate

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionNovember 2023
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 geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating31.4 US tons
Inventory rating23.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length136 ft (41.5 m)
Longest span62 ft (18.9 m)
Deck width42 ft (12.8 m)
Roadway width38 ft (11.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic9,300 (2023)
Projected traffic9,141 by 2046
Trucks44%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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 I-39 Sb/Us 51 SB over Tomahawk Creek built?

It was built in 1979, making it 46 years old in 2025.

What condition is I-39 Sb/Us 51 SB over Tomahawk 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 November 2023.

How much traffic does I-39 Sb/Us 51 SB over Tomahawk Creek carry?

About 9,300 vehicles per day (2023 count), of which roughly 44% are trucks.

How long is I-39 Sb/Us 51 SB over Tomahawk Creek?

The structure is 136 ft (41.5 m) long with a longest span of 62 ft (18.9 m) and a deck 42 ft wide.

Who owns I-39 Sb/Us 51 SB over Tomahawk Creek?

It is owned by the State Highway Agency.