Structure 48003600000000 · Knox County, IL

Ontario Road over I-74

Carries Ontario Road over I-74, .5 Mi N Henderson CR.

Overall conditionPoor

Set by its lowest-rated component: Deck at 3 of 9.

How ratings work
Decksets the rating3/9 · Serious
Superstructure4/9 · Poor
Substructure6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT222 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 3/9 · sets the ratingSuperstructure 4/9Substructure 6/9

222 ft end to end, longest span 67 ft: about 3 semi-trucks nose to tail. Lengths and the semi-truck on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a multi-beam bridge.

Built196660 years old
Length222.1 ft67.7 m
Daily traffic200counted 2022
Last inspectedDecember 2023every 12 months

Location

StateIllinois
CountyKnox
Location.5 Mi N Henderson CR
CarriesOntario Road
CrossesI-74
Coordinates41.07846, -90.33437

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length222.1 ft (67.7 m)
Max Span66.9 ft (20.4 m)
Deck Width31.8 ft (9.7 m)
Deck Area656.7 sq m
Main Spans4
Year Built1966

Traffic

Avg Daily Traffic200 (2022)
Truck Traffic5%
Lanes On Bridge2
Lanes Under Bridge4

Inspection & Ownership

Last InspectionDecember 2023
Inspection FrequencyEvery 12 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number048003600000000

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.

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