Structure 16051800000000 · Cook County, IL

Il 171 & 79 ST EB over US 12 20 45 Mannheim

Carries Il 171 & 79 ST EB over US 12 20 45 Mannheim, 0.1 M SW US 45.

Overall conditionPoor

Set by its lowest-rated component: Deck at 4 of 9.

How ratings work
Decksets the rating4/9 · Poor
Superstructure5/9 · Fair
Substructure5/9 · Fair
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT180 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 4/9 · sets the ratingSuperstructure 5/9Substructure 5/9

180 ft end to end, longest span 65 ft: about 2 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.

Built1959rebuilt 1998
Length179.8 ft54.8 m
Daily traffic17,300counted 2022
Last inspectedSeptember 2023every 24 months

Location

StateIllinois
CountyCook
Location0.1 M SW US 45
CarriesIl 171 & 79 ST EB
CrossesUS 12 20 45 Mannheim
Coordinates41.74546, -87.85270

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length179.8 ft (54.8 m)
Max Span65.0 ft (19.8 m)
Deck Width36.4 ft (11.1 m)
Deck Area608.3 sq m
Main Spans3
Year Built1959 (reconstructed 1998)

Traffic

Avg Daily Traffic17,300 (2022)
Truck Traffic22%
Lanes On Bridge2
Lanes Under Bridge2

Inspection & Ownership

Last InspectionSeptember 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number016051800000000

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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