US Bridges

TR 18 over Sangamon River

Fair

Piatt County, Illinois · 1 MI SW Allerton Par · Structure no. 074322500000000

Built
1991
34 years old
Condition
Fair
inspected February 2025
Type
Stringer/Multi-beam or Girder
Steel
Length
511 ft
4 main spans
Daily traffic
125
2020 count
Owner
Town / Township
Town or Township Highway Agency

About this bridge

TR 18 over Sangamon River is a steel stringer/multi-beam or girder carrying TR 18 over Sangamon River in Piatt 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 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 125 vehicles a day, roughly 8% of them trucks, projected to reach 126 by 2046. The structure is 511 ft (155.8 m) long and 30 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesTR 18
CrossesSangamon River
Location1 MI SW Allerton Par
RouteCounty Highway 0
CountyPiatt County
StateIllinois
Coordinates39.97998, -88.68405
Functional classRural Local

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.
Superstructure8 Very GoodNo problems noted.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionFebruary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than 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 rating48.9 US tons
Inventory rating35.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length511 ft (155.8 m)
Longest span142 ft (43.3 m)
Deck width30 ft (9.1 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic125 (2020)
Projected traffic126 by 2046
Trucks8%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerTown or Township Highway Agency
Maintained byTown or Township 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 TR 18 over Sangamon River built?

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

What condition is TR 18 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 February 2025.

How much traffic does TR 18 over Sangamon River carry?

About 125 vehicles per day (2020 count), of which roughly 8% are trucks.

How long is TR 18 over Sangamon River?

The structure is 511 ft (155.8 m) long with a longest span of 142 ft (43.3 m) and a deck 30 ft wide.

Who owns TR 18 over Sangamon River?

It is owned by the Town or Township Highway Agency.