US Bridges

TR 171 over Sangamon River

PoorPosted for load

Sangamon County, Illinois · 2.0 E of Clear Lake · Structure no. 084310600000000

Built
1950
75 years old
Condition
Poor
inspected April 2023
Type
Truss - Thru
Steel
Length
287 ft
2 main spans
Daily traffic
175
2022 count
Owner
Town / Township
Town or Township Highway Agency

About this bridge

TR 171 over Sangamon River is a steel truss - thru carrying TR 171 over Sangamon River in Sangamon County, Illinois. It was built in 1950, so it is 75 years old, older than the Illinois average of 45.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. Its operating status is: posted for load restriction.

It carries about 175 vehicles a day, roughly 3% of them trucks, projected to reach 429 by 2046. The structure is 287 ft (87.5 m) long and 22 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesTR 171
CrossesSangamon River
Location2.0 E of Clear Lake
RouteCounty Highway 0
CountySangamon County
StateIllinois
Coordinates39.82301, -89.54447
Functional classUrban Local

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating18.5 US tons
Inventory rating11 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckConcrete, cast-in-place
Main spans2
Design loadH 15
Structure length287 ft (87.5 m)
Longest span141 ft (43 m)
Deck width22 ft (6.7 m)
Roadway width20 ft (6.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic175 (2022)
Projected traffic429 by 2046
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$834,000
NavigationNo navigation control on waterway

Frequently asked questions

When was TR 171 over Sangamon River built?

It was built in 1950, making it 75 years old in 2025.

What condition is TR 171 over Sangamon River in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in April 2023.

How much traffic does TR 171 over Sangamon River carry?

About 175 vehicles per day (2022 count), of which roughly 3% are trucks.

How long is TR 171 over Sangamon River?

The structure is 287 ft (87.5 m) long with a longest span of 141 ft (43 m) and a deck 22 ft wide.

Who owns TR 171 over Sangamon River?

It is owned by the Town or Township Highway Agency.