US Bridges

FAP 322(SB)(US 51) over Sangamon River

Fair

Macon County, Illinois · 1 MI S Harristown · Structure no. 058009900000000

Built
1976
49 years old, rebuilt 2018
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
755 ft
10 main spans
Daily traffic
5,900
2023 count
Owner
State
State Highway Agency

About this bridge

FAP 322(SB)(US 51) over Sangamon River is a steel continuous stringer/multi-beam or girder carrying FAP 322(SB)(US 51) over Sangamon River in Macon County, Illinois. It was built in 1976 and reconstructed in 2018, so it is 49 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 5,900 vehicles a day, roughly 25% of them trucks, projected to reach 2,727 by 2046. The structure is 755 ft (230.1 m) long and 42 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesFAP 322(SB)(US 51)
CrossesSangamon River
Location1 MI S Harristown
RouteU.S. Route 51
CountyMacon County
StateIllinois
Coordinates39.82427, -89.03784
Functional classUrban Principal Arterial - Other Freeway or Expressway

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.
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 protection7 GoodSome minor problems.
Last inspectionJune 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 adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.6 US tons
Inventory rating46.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans10
Design loadHS 20
Structure length755 ft (230.1 m)
Longest span120 ft (36.6 m)
Deck width42 ft (12.8 m)
Roadway width38 ft (11.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,900 (2023)
Projected traffic2,727 by 2046
Trucks25%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$4.4 million
NavigationNo navigation control on waterway

Frequently asked questions

When was FAP 322(SB)(US 51) over Sangamon River built?

It was built in 1976, making it 49 years old in 2025. It was reconstructed in 2018.

What condition is FAP 322(SB)(US 51) over Sangamon River 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 June 2023.

How much traffic does FAP 322(SB)(US 51) over Sangamon River carry?

About 5,900 vehicles per day (2023 count), of which roughly 25% are trucks.

How long is FAP 322(SB)(US 51) over Sangamon River?

The structure is 755 ft (230.1 m) long with a longest span of 120 ft (36.6 m) and a deck 42 ft wide.

Who owns FAP 322(SB)(US 51) over Sangamon River?

It is owned by the State Highway Agency.