US Bridges

Il 121 over Salt Creek

Fair

Logan County, Illinois · 3.9M N IL54-MT Pul.* · Structure no. 054002100000000

Built
1928
97 years old, rebuilt 1990
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
573 ft
3 main spans
Daily traffic
3,500
2023 count
Owner
State
State Highway Agency

About this bridge

Il 121 over Salt Creek is a steel continuous stringer/multi-beam or girder carrying Il 121 over Salt Creek in Logan County, Illinois. It was built in 1928 and reconstructed in 1990, so it is 97 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 3,500 vehicles a day, roughly 19% of them trucks, projected to reach 3,728 by 2046. The structure is 573 ft (174.7 m) long and 35 ft wide. If it were closed, the detour would be 19.3 mi (31 km).

Location

Open in Google Maps
CarriesIl 121
CrossesSalt Creek
Location3.9M N IL54-MT Pul.*
RouteState Highway 121
CountyLogan County
StateIllinois
Coordinates40.05438, -89.28203
Functional classRural Principal Arterial - Other

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 protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating60.4 US tons
Inventory rating36 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3 (+7 approach)
Design loadHS 20
Structure length573 ft (174.7 m)
Longest span69 ft (21 m)
Deck width35 ft (10.7 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,500 (2023)
Projected traffic3,728 by 2046
Trucks19%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed19.3 mi (31 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Il 121 over Salt Creek built?

It was built in 1928, making it 97 years old in 2025. It was reconstructed in 1990.

What condition is Il 121 over Salt 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 July 2023.

How much traffic does Il 121 over Salt Creek carry?

About 3,500 vehicles per day (2023 count), of which roughly 19% are trucks.

How long is Il 121 over Salt Creek?

The structure is 573 ft (174.7 m) long with a longest span of 69 ft (21 m) and a deck 35 ft wide.

Who owns Il 121 over Salt Creek?

It is owned by the State Highway Agency.