US Bridges

I-39/US 51 NB over Norfolk & Southern RR

Fair

LaSalle County, Illinois · 1.48 MI N of Ill 18 · Structure no. 050021100000000

Built
1988
37 years old
Condition
Fair
inspected January 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
138 ft
3 main spans
Daily traffic
9,700
2023 count
Owner
State
State Highway Agency

About this bridge

I-39/US 51 NB over Norfolk & Southern RR is a steel continuous stringer/multi-beam or girder carrying I-39/US 51 NB over Norfolk & Southern RR in LaSalle County, Illinois. It was built in 1988, so it is 37 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 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 9,700 vehicles a day, roughly 36% of them trucks, projected to reach 9,494 by 2046. The structure is 138 ft (42.1 m) long and 43 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI-39/US 51 NB
CrossesNorfolk & Southern RR
Location1.48 MI N of Ill 18
RouteInterstate 39
CountyLaSalle County
StateIllinois
Coordinates41.14035, -89.07542
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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionJanuary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating78.3 US tons
Inventory rating46.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length138 ft (42.1 m)
Longest span50 ft (15.2 m)
Deck width43 ft (13.1 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic9,700 (2023)
Projected traffic9,494 by 2046
Trucks36%
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 Norfolk & Southern RR built?

It was built in 1988, making it 37 years old in 2025.

What condition is I-39/US 51 NB over Norfolk & Southern 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 January 2023.

How much traffic does I-39/US 51 NB over Norfolk & Southern RR carry?

About 9,700 vehicles per day (2023 count), of which roughly 36% are trucks.

How long is I-39/US 51 NB over Norfolk & Southern RR?

The structure is 138 ft (42.1 m) long with a longest span of 50 ft (15.2 m) and a deck 43 ft wide.

Who owns I-39/US 51 NB over Norfolk & Southern RR?

It is owned by the State Highway Agency.