US Bridges

I-57 (nb) over Flat Branch

Fair

Coles County, Illinois · .5 MI N Humboldt RD · Structure no. 015001100000000

Built
1967
58 years old, rebuilt 2001
Condition
Fair
inspected November 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
115 ft
3 main spans
Daily traffic
11,350
2023 count
Owner
State
State Highway Agency

About this bridge

I-57 (nb) over Flat Branch is a steel continuous stringer/multi-beam or girder carrying I-57 (nb) over Flat Branch in Coles County, Illinois. It was built in 1967 and reconstructed in 2001, so it is 58 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 11,350 vehicles a day, roughly 38% of them trucks, projected to reach 11,817 by 2046. The structure is 115 ft (34.9 m) long and 45 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-57 (nb)
CrossesFlat Branch
Location.5 MI N Humboldt RD
RouteInterstate 57
CountyColes County
StateIllinois
Coordinates39.60315, -88.2996
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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionNovember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating98.2 US tons
Inventory rating63.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length115 ft (34.9 m)
Longest span41 ft (12.6 m)
Deck width45 ft (13.6 m)
Roadway width41 ft (12.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11,350 (2023)
Projected traffic11,817 by 2046
Trucks38%
Lanes on structure1
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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$724,000
NavigationNo navigation control on waterway

Frequently asked questions

When was I-57 (nb) over Flat Branch built?

It was built in 1967, making it 58 years old in 2025. It was reconstructed in 2001.

What condition is I-57 (nb) over Flat Branch 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 November 2024.

How much traffic does I-57 (nb) over Flat Branch carry?

About 11,350 vehicles per day (2023 count), of which roughly 38% are trucks.

How long is I-57 (nb) over Flat Branch?

The structure is 115 ft (34.9 m) long with a longest span of 41 ft (12.6 m) and a deck 45 ft wide.

Who owns I-57 (nb) over Flat Branch?

It is owned by the State Highway Agency.