US Bridges

TR 170 over Macoupin Crk

PoorPosted for load

Macoupin County, Illinois · Beaver Dam St. Park · Structure no. 059311100000000

Built
1900
125 years old
Condition
Poor
inspected February 2023
Type
Truss - Thru
Steel
Length
140 ft
1 main span
Daily traffic
50
2021 count
Owner
Town / Township
Town or Township Highway Agency

About this bridge

TR 170 over Macoupin Crk is a steel truss - thru carrying TR 170 over Macoupin Crk in Macoupin County, Illinois. It was built in 1900, so it is 125 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 50 vehicles a day, roughly 36% of them trucks, projected to reach 51 by 2046. The structure is 140 ft (42.7 m) long and 14 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesTR 170
CrossesMacoupin Crk
LocationBeaver Dam St. Park
RouteCounty Highway 0
CountyMacoupin County
StateIllinois
Coordinates39.20685, -90.00062
Functional classRural 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
Deck7 GoodSome minor problems.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionFebruary 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 geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating8.6 US tons
Inventory rating5 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckWood or timber
Main spans1 (+3 approach)
Design loadUnknown
Structure length140 ft (42.7 m)
Longest span90 ft (27.4 m)
Deck width14 ft (4.4 m)
Roadway width13 ft (4.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic50 (2021)
Projected traffic51 by 2046
Trucks36%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerTown or Township Highway Agency
Maintained byTown or Township Highway Agency
Historic statusEligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$269,000
NavigationNo navigation control on waterway

Frequently asked questions

When was TR 170 over Macoupin Crk built?

It was built in 1900, making it 125 years old in 2025.

What condition is TR 170 over Macoupin Crk 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 February 2023.

How much traffic does TR 170 over Macoupin Crk carry?

About 50 vehicles per day (2021 count), of which roughly 36% are trucks.

How long is TR 170 over Macoupin Crk?

The structure is 140 ft (42.7 m) long with a longest span of 90 ft (27.4 m) and a deck 14 ft wide.

Who owns TR 170 over Macoupin Crk?

It is owned by the Town or Township Highway Agency.