US Bridges

Ill 9 over I-55/I-74

Fair

McLean County, Illinois · Interchange Ill 9 · Structure no. 057008800000000

Built
1964
61 years old, rebuilt 2003
Condition
Fair
inspected May 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
268 ft
4 main spans
Daily traffic
19,100
2023 count
Owner
State
State Highway Agency

About this bridge

Ill 9 over I-55/I-74 is a steel continuous stringer/multi-beam or girder carrying Ill 9 over I-55/I-74 in McLean County, Illinois. It was built in 1964 and reconstructed in 2003, so it is 61 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 19,100 vehicles a day, roughly 18% of them trucks, projected to reach 17,271 by 2046. The structure is 268 ft (81.7 m) long and 110 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesIll 9
CrossesI-55/I-74
LocationInterchange Ill 9
RouteU.S. Route 150
CountyMcLean County
StateIllinois
Coordinates40.48484, -89.02837
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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating98.2 US tons
Inventory rating64.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20 + Mod
Structure length268 ft (81.7 m)
Longest span87 ft (26.6 m)
Deck width110 ft (33.4 m)
Roadway width102 ft (31.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic19,100 (2023)
Projected traffic17,271 by 2046
Trucks18%
Lanes on structure6
Traffic directionTwo-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed3.1 mi (5 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 proposedWidening with deck rehabilitation or replacement
Estimated improvement cost$2.9 million
NavigationNot applicable (no waterway)

Frequently asked questions

When was Ill 9 over I-55/I-74 built?

It was built in 1964, making it 61 years old in 2025. It was reconstructed in 2003.

What condition is Ill 9 over I-55/I-74 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 2024.

How much traffic does Ill 9 over I-55/I-74 carry?

About 19,100 vehicles per day (2023 count), of which roughly 18% are trucks.

How long is Ill 9 over I-55/I-74?

The structure is 268 ft (81.7 m) long with a longest span of 87 ft (26.6 m) and a deck 110 ft wide.

Who owns Ill 9 over I-55/I-74?

It is owned by the State Highway Agency.