US Bridges

Ch 21 over I-74

Poor

Knox County, Illinois · 3 MI E of Knoxville · Structure no. 048004700000000

Built
1967
58 years old
Condition
Poor
inspected November 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
230 ft
4 main spans
Daily traffic
75
2022 count
Owner
State
State Highway Agency

About this bridge

Ch 21 over I-74 is a steel continuous stringer/multi-beam or girder carrying Ch 21 over I-74 in Knox County, Illinois. It was built in 1967, so it is 58 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 75 vehicles a day, projected to reach 76 by 2046. The structure is 230 ft (70.1 m) long and 30 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesCh 21
CrossesI-74
Location3 MI E of Knoxville
RouteCounty Highway 0
CountyKnox County
StateIllinois
Coordinates40.90277, -90.21257
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
Deck4 PoorAdvanced section loss, deterioration, spalling or scour.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionNovember 2024
Inspection intervalevery 12 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating47.5 US tons
Inventory rating28.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 15
Structure length230 ft (70.1 m)
Longest span71 ft (21.6 m)
Deck width30 ft (9.1 m)
Roadway width27 ft (8.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic75 (2022)
Projected traffic76 by 2046
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed6.2 mi (10 km)
TollOn a free road
National Highway SystemNo

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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Ch 21 over I-74 built?

It was built in 1967, making it 58 years old in 2025.

What condition is Ch 21 over I-74 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 November 2024.

How much traffic does Ch 21 over I-74 carry?

About 75 vehicles per day (2022 count).

How long is Ch 21 over I-74?

The structure is 230 ft (70.1 m) long with a longest span of 71 ft (21.6 m) and a deck 30 ft wide.

Who owns Ch 21 over I-74?

It is owned by the State Highway Agency.