US Bridges

I-57 (sb) over S Fork Flat Branch

Fair

Coles County, Illinois · .5 MI S Humboldt · Structure no. 015001000000000

Built
1967
58 years old
Condition
Fair
inspected July 2023
Type
Slab
Concrete Continuous
Length
93 ft
3 main spans
Daily traffic
11,350
2023 count
Owner
State
State Highway Agency

About this bridge

I-57 (sb) over S Fork Flat Branch is a concrete continuous slab carrying I-57 (sb) over S Fork Flat Branch in Coles County, Illinois. It was built in 1967, 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 93 ft (28.2 m) long and 44 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-57 (sb)
CrossesS Fork Flat Branch
Location.5 MI S Humboldt
RouteInterstate 57
CountyColes County
StateIllinois
Coordinates39.59606, -88.30451
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.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating56.4 US tons
Inventory rating34 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length93 ft (28.2 m)
Longest span34 ft (10.4 m)
Deck width44 ft (13.3 m)
Roadway width39 ft (11.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11,350 (2023)
Projected traffic11,817 by 2046
Trucks38%
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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$566,000
NavigationNo navigation control on waterway

Frequently asked questions

When was I-57 (sb) over S Fork Flat Branch built?

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

What condition is I-57 (sb) over S Fork 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 July 2023.

How much traffic does I-57 (sb) over S Fork Flat Branch carry?

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

How long is I-57 (sb) over S Fork Flat Branch?

The structure is 93 ft (28.2 m) long with a longest span of 34 ft (10.4 m) and a deck 44 ft wide.

Who owns I-57 (sb) over S Fork Flat Branch?

It is owned by the State Highway Agency.