Structure 71004000000000 · Ogle County, IL

Ill 72 over Rock River

Carries Ill 72 over Rock River, E. Edge Of Byron.

Overall conditionFair

Set by its lowest-rated component: Substructure at 6 of 9.

How ratings work
Deck7/9 · Good
Superstructure7/9 · Good
Substructuresets the rating6/9 · Satisfactory
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT712 FT OVERALL100 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 6/9 · sets the rating

712 ft end to end, longest span 78 ft: about 2.0 football fields. 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.

Built1940rebuilt 1990
Length711.9 ft217 m
Daily traffic7,100counted 2023
Last inspectedAugust 2024every 24 months

Location

StateIllinois
CountyOgle
LocationE. Edge Of Byron
CarriesIll 72
CrossesRock River
Coordinates42.12293, -89.25577

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length711.9 ft (217 m)
Max Span78.1 ft (23.8 m)
Deck Width45.6 ft (13.9 m)
Deck Area3016.3 sq m
Main Spans10
Year Built1940 (reconstructed 1990)

Traffic

Avg Daily Traffic7,100 (2023)
Truck Traffic3%
Lanes On Bridge2

Inspection & Ownership

Last InspectionAugust 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure Number071004000000000

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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