US Bridges

I-55 (nb) over Macoupin Creek

Fair

Montgomery County, Illinois · .3M S Farmrsvle Int. · Structure no. 068003800000000

Built
1972
53 years old, rebuilt 2009
Condition
Fair
inspected December 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
62 ft
1 main span
Daily traffic
14,400
2021 count
Owner
State
State Highway Agency

About this bridge

I-55 (nb) over Macoupin Creek is a steel stringer/multi-beam or girder carrying I-55 (nb) over Macoupin Creek in Montgomery County, Illinois. It was built in 1972 and reconstructed in 2009, so it is 53 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 14,400 vehicles a day, roughly 28% of them trucks, projected to reach 14,544 by 2046. The structure is 62 ft (19 m) long and 43 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-55 (nb)
CrossesMacoupin Creek
Location.3M S Farmrsvle Int.
RouteInterstate 55
CountyMontgomery County
StateIllinois
Coordinates39.43877, -89.64372
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.
Channel and channel protection7 GoodSome minor problems.
Last inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating91.8 US tons
Inventory rating55 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length62 ft (19 m)
Longest span55 ft (16.9 m)
Deck width43 ft (13.2 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic14,400 (2021)
Projected traffic14,544 by 2046
Trucks28%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
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—
NavigationNo navigation control on waterway

Frequently asked questions

When was I-55 (nb) over Macoupin Creek built?

It was built in 1972, making it 53 years old in 2025. It was reconstructed in 2009.

What condition is I-55 (nb) over Macoupin Creek 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 December 2023.

How much traffic does I-55 (nb) over Macoupin Creek carry?

About 14,400 vehicles per day (2021 count), of which roughly 28% are trucks.

How long is I-55 (nb) over Macoupin Creek?

The structure is 62 ft (19 m) long with a longest span of 55 ft (16.9 m) and a deck 43 ft wide.

Who owns I-55 (nb) over Macoupin Creek?

It is owned by the State Highway Agency.