US Bridges

I-39 & US 51 NB over Soo Line RR

Fair

Ogle County, Illinois · 0.25 MI S of ILL.72 · Structure no. 071004900000000

Built
1981
44 years old
Condition
Fair
inspected March 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
163 ft
3 main spans
Daily traffic
16,100
2023 count
Owner
State
State Highway Agency

About this bridge

I-39 & US 51 NB over Soo Line RR is a prestressed concrete continuous stringer/multi-beam or girder carrying I-39 & US 51 NB over Soo Line RR in Ogle County, Illinois. It was built in 1981, so it is 44 years old, younger 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 16,100 vehicles a day, roughly 32% of them trucks, projected to reach 14,716 by 2046. The structure is 163 ft (49.8 m) long and 42 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-39 & US 51 NB
CrossesSoo Line RR
Location0.25 MI S of ILL.72
RouteInterstate 39
CountyOgle County
StateIllinois
Coordinates42.09756, -89.02259
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.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating98.2 US tons
Inventory rating72.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length163 ft (49.8 m)
Longest span57 ft (17.5 m)
Deck width42 ft (12.8 m)
Roadway width38 ft (11.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic16,100 (2023)
Projected traffic14,716 by 2046
Trucks32%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesRailroad
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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-39 & US 51 NB over Soo Line RR built?

It was built in 1981, making it 44 years old in 2025.

What condition is I-39 & US 51 NB over Soo Line RR 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 March 2023.

How much traffic does I-39 & US 51 NB over Soo Line RR carry?

About 16,100 vehicles per day (2023 count), of which roughly 32% are trucks.

How long is I-39 & US 51 NB over Soo Line RR?

The structure is 163 ft (49.8 m) long with a longest span of 57 ft (17.5 m) and a deck 42 ft wide.

Who owns I-39 & US 51 NB over Soo Line RR?

It is owned by the State Highway Agency.