US Bridges

I-39 over SE Half Conveyor B

Fair

LaSalle County, Illinois · 0.05 M S of US 6 · Structure no. 050200900000000

Built
1961
64 years old, rebuilt 1985
Condition
Fair
inspected February 2023
Type
Culvert
Concrete
Length
29 ft
1 main span
Daily traffic
19,400
2023 count
Owner
State
State Highway Agency

About this bridge

I-39 over SE Half Conveyor B is a concrete culvert carrying I-39 over SE Half Conveyor B in LaSalle County, Illinois. It was built in 1961 and reconstructed in 1985, so it is 64 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 19,400 vehicles a day, roughly 38% of them trucks, projected to reach 19,291 by 2046. The structure is 29 ft (8.7 m) long and 143 ft wide.

Location

Open in Google Maps
CarriesI-39
CrossesSE Half Conveyor B
Location0.05 M S of US 6
RouteInterstate 39
CountyLaSalle County
StateIllinois
Coordinates41.33578, -89.07164
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
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating98.2 US tons
Inventory rating98.2 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans1
Design loadHS 20
Structure length29 ft (8.7 m)
Longest span26 ft (7.8 m)
Deck width143 ft (43.6 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic19,400 (2023)
Projected traffic19,291 by 2046
Trucks38%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesOther
Detour if closed—
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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$516,000
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-39 over SE Half Conveyor B built?

It was built in 1961, making it 64 years old in 2025. It was reconstructed in 1985.

What condition is I-39 over SE Half Conveyor B 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 February 2023.

How much traffic does I-39 over SE Half Conveyor B carry?

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

How long is I-39 over SE Half Conveyor B?

The structure is 29 ft (8.7 m) long with a longest span of 26 ft (7.8 m) and a deck 143 ft wide.

Who owns I-39 over SE Half Conveyor B?

It is owned by the State Highway Agency.