US Bridges

I-55 Busn Loop over Union Pacific RR & Old 6

Fair

McLean County, Illinois · 2.8 MI N of Ill 9 · Structure no. 057006900000000

Built
1939
86 years old, rebuilt 2003
Condition
Fair
inspected May 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
442 ft
6 main spans
Daily traffic
21,300
2023 count
Owner
State
State Highway Agency

About this bridge

I-55 Busn Loop over Union Pacific RR & Old 6 is a steel continuous stringer/multi-beam or girder carrying I-55 Busn Loop over Union Pacific RR & Old 6 in McLean County, Illinois. It was built in 1939 and reconstructed in 2003, so it is 86 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 21,300 vehicles a day, roughly 6% of them trucks, projected to reach 19,291 by 2046. The structure is 442 ft (134.6 m) long and 87 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

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CarriesI-55 Busn Loop
CrossesUnion Pacific RR & Old 6
Location2.8 MI N of Ill 9
RouteInterstate 55
CountyMcLean County
StateIllinois
Coordinates40.52981, -88.95162
Functional classUrban Other Principal Arterial

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating87.2 US tons
Inventory rating44.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans6
Design loadHS 20
Structure length442 ft (134.6 m)
Longest span86 ft (26.3 m)
Deck width87 ft (26.5 m)
Roadway width81 ft (24.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic21,300 (2023)
Projected traffic19,291 by 2046
Trucks6%
Lanes on structure6
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway and railroad
Detour if closed5 mi (8 km)
TollOn a free road
National Highway SystemYes

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$6.1 million
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-55 Busn Loop over Union Pacific RR & Old 6 built?

It was built in 1939, making it 86 years old in 2025. It was reconstructed in 2003.

What condition is I-55 Busn Loop over Union Pacific RR & Old 6 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 May 2023.

How much traffic does I-55 Busn Loop over Union Pacific RR & Old 6 carry?

About 21,300 vehicles per day (2023 count), of which roughly 6% are trucks.

How long is I-55 Busn Loop over Union Pacific RR & Old 6?

The structure is 442 ft (134.6 m) long with a longest span of 86 ft (26.3 m) and a deck 87 ft wide.

Who owns I-55 Busn Loop over Union Pacific RR & Old 6?

It is owned by the State Highway Agency.