US Bridges

FAP 320(IL 121) over NS RR

Fair

Macon County, Illinois · In Decatur · Structure no. 058012000000000

Built
1991
34 years old
Condition
Fair
inspected April 2024
Type
Box Beam or Girders - Single or Spread
Steel Continuous
Length
2,320 ft
16 main spans
Daily traffic
18,900
2023 count
Owner
State
State Highway Agency

About this bridge

FAP 320(IL 121) over NS RR is a steel continuous box beam or girders - single or spread carrying FAP 320(IL 121) over NS RR in Macon County, Illinois. It was built in 1991, so it is 34 years old, younger 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 18,900 vehicles a day, roughly 6% of them trucks, projected to reach 19,392 by 2046. The structure is 2,320 ft (707.2 m) long and 64 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesFAP 320(IL 121)
CrossesNS RR
LocationIn Decatur
RouteState Highway 121
CountyMacon County
StateIllinois
Coordinates39.85312, -88.92652
Functional classUrban Other Principal Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionApril 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating98.2 US tons
Inventory rating81 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans16
Design loadHS 20 + Mod
Structure length2,320 ft (707.2 m)
Longest span200 ft (61 m)
Deck width64 ft (19.4 m)
Roadway width52 ft (15.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic18,900 (2023)
Projected traffic19,392 by 2046
Trucks6%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesRailroad
Detour if closed1.9 mi (3 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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was FAP 320(IL 121) over NS RR built?

It was built in 1991, making it 34 years old in 2025.

What condition is FAP 320(IL 121) over NS RR 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 April 2024.

How much traffic does FAP 320(IL 121) over NS RR carry?

About 18,900 vehicles per day (2023 count), of which roughly 6% are trucks.

How long is FAP 320(IL 121) over NS RR?

The structure is 2,320 ft (707.2 m) long with a longest span of 200 ft (61 m) and a deck 64 ft wide.

Who owns FAP 320(IL 121) over NS RR?

It is owned by the State Highway Agency.