US Bridges

Ill 47 over Armstrong & B & O RR

Poor

Grundy County, Illinois · .57 S of US 6 West · Structure no. 032008600000000

Built
1978
47 years old
Condition
Poor
inspected February 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
396 ft
6 main spans
Daily traffic
21,000
2023 count
Owner
State
State Highway Agency

About this bridge

Ill 47 over Armstrong & B & O RR is a steel continuous stringer/multi-beam or girder carrying Ill 47 over Armstrong & B & O RR in Grundy County, Illinois. It was built in 1978, so it is 47 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.

It carries about 21,000 vehicles a day, roughly 9% of them trucks, projected to reach 26,040 by 2046. The structure is 396 ft (120.7 m) long and 68 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesIll 47
CrossesArmstrong & B & O RR
Location.57 S of US 6 West
RouteState Highway 47
CountyGrundy County
StateIllinois
Coordinates41.36425, -88.42182
Functional classUrban Other Principal Arterial

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
Deck4 PoorAdvanced section loss, deterioration, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Last inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment7: Better than present minimum criteria
Operating rating73.2 US tons
Inventory rating44 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans6
Design loadHS 20
Structure length396 ft (120.7 m)
Longest span72 ft (21.9 m)
Deck width68 ft (20.7 m)
Roadway width56 ft (17.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic21,000 (2023)
Projected traffic26,040 by 2046
Trucks9%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway and railroad
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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Ill 47 over Armstrong & B & O RR built?

It was built in 1978, making it 47 years old in 2025.

What condition is Ill 47 over Armstrong & B & O RR 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 Ill 47 over Armstrong & B & O RR carry?

About 21,000 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is Ill 47 over Armstrong & B & O RR?

The structure is 396 ft (120.7 m) long with a longest span of 72 ft (21.9 m) and a deck 68 ft wide.

Who owns Ill 47 over Armstrong & B & O RR?

It is owned by the State Highway Agency.