US Bridges

I-39 US 51 over Il Rv/Il 351/ Bo RR

Fair

LaSalle County, Illinois · 2.82 MI S of I-80 · Structure no. 050019100000000

Built
1984
41 years old, rebuilt 2007
Condition
Fair
inspected August 2024
Type
Arch - Thru
Steel
Length
7,121 ft
1 main span
Daily traffic
19,400
2023 count
Owner
State
State Highway Agency

About this bridge

I-39 US 51 over Il Rv/Il 351/ Bo RR is a steel arch - thru carrying I-39 US 51 over Il Rv/Il 351/ Bo RR in LaSalle County, Illinois. It was built in 1984 and reconstructed in 2007, so it is 41 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 19,400 vehicles a day, roughly 38% of them trucks, projected to reach 19,291 by 2046. The structure is 7,121 ft (2,170.5 m) long and 87 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI-39 US 51
CrossesIl Rv/Il 351/ Bo RR
Location2.82 MI S of I-80
RouteInterstate 39
CountyLaSalle County
StateIllinois
Coordinates41.31049, -89.08283
Functional classUrban 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 inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry9: Superior to present desirable criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating55.7 US tons
Inventory rating33.6 US tons

Structure

Structure typeArch - Thru
MaterialSteel
DeckConcrete, cast-in-place
Main spans1 (+43 approach)
Design loadHS 20
Structure length7,121 ft (2,170.5 m)
Longest span620 ft (189.1 m)
Deck width87 ft (26.4 m)
Roadway width82 ft (25 m)
Vertical clearance over deck19 ft (5.9 m)

Traffic and service

Average daily traffic19,400 (2023)
Projected traffic19,291 by 2046
Trucks38%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway, waterway and railroad
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—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was I-39 US 51 over Il Rv/Il 351/ Bo RR built?

It was built in 1984, making it 41 years old in 2025. It was reconstructed in 2007.

What condition is I-39 US 51 over Il Rv/Il 351/ Bo 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 August 2024.

How much traffic does I-39 US 51 over Il Rv/Il 351/ Bo RR carry?

About 19,400 vehicles per day (2023 count), of which roughly 38% are trucks.

How long is I-39 US 51 over Il Rv/Il 351/ Bo RR?

The structure is 7,121 ft (2,170.5 m) long with a longest span of 620 ft (189.1 m) and a deck 87 ft wide.

Who owns I-39 US 51 over Il Rv/Il 351/ Bo RR?

It is owned by the State Highway Agency.