US Bridges

I-55 SB over Salt Creek Overflow

Fair

Logan County, Illinois · 1.6M S Il 10 · Structure no. 054004400000000

Built
1973
52 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
206 ft
3 main spans
Daily traffic
13,750
2023 count
Owner
State
State Highway Agency

About this bridge

I-55 SB over Salt Creek Overflow is a prestressed concrete stringer/multi-beam or girder carrying I-55 SB over Salt Creek Overflow in Logan County, Illinois. It was built in 1973, so it is 52 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 5 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 13,750 vehicles a day, roughly 32% of them trucks, projected to reach 13,230 by 2046. The structure is 206 ft (62.8 m) long and 58 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

CarriesI-55 SB
CrossesSalt Creek Overflow
Location1.6M S Il 10
RouteInterstate 55
Coordinates40.13455, -89.41681
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
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating58.2 US tons
Inventory rating36 US tons

Structure

MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length206 ft (62.8 m)
Longest span68 ft (20.6 m)
Deck width58 ft (17.7 m)
Roadway width54 ft (16.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,750 (2023)
Projected traffic13,230 by 2046
Trucks32%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesRelief for waterway
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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-55 SB over Salt Creek Overflow built?

It was built in 1973, making it 52 years old in 2025.

What condition is I-55 SB over Salt Creek Overflow 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 August 2023.

How much traffic does I-55 SB over Salt Creek Overflow carry?

About 13,750 vehicles per day (2023 count), of which roughly 32% are trucks.

How long is I-55 SB over Salt Creek Overflow?

The structure is 206 ft (62.8 m) long with a longest span of 68 ft (20.6 m) and a deck 58 ft wide.

Who owns I-55 SB over Salt Creek Overflow?

It is owned by the State Highway Agency.