Structure 16086700000000 · Cook County, IL

31st ST over I-294 Tri State Toll

Carries 31st ST over I-294 Tri State Toll, 1 M N US 34.

Overall conditionFair

Set by its lowest-rated component: Superstructure at 5 of 9.

How ratings work
Deck7/9 · Good
Superstructuresets the rating5/9 · Fair
Substructure7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT290 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 5/9 · sets the ratingSubstructure 7/9

290 ft end to end, longest span 118 ft: about 4 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.

Built1958rebuilt 1992
Length290.4 ft88.5 m
Daily traffic14,700counted 2022
Last inspectedMarch 2023every 24 months

Location

StateIllinois
CountyCook
Location1 M N US 34
Carries31st ST
CrossesI-294 Tri State Toll
Coordinates41.83315, -87.91866

Physical Characteristics

MaterialPrestressed Concrete Continuous
DesignStringer/Multi-beam
Total Length290.4 ft (88.5 m)
Max Span118.4 ft (36.1 m)
Deck Width71.2 ft (21.7 m)
Deck Area1920.5 sq m
Main Spans2
Year Built1958 (reconstructed 1992)

Traffic

Avg Daily Traffic14,700 (2022)
Truck Traffic3%
Lanes On Bridge4
Lanes Under Bridge6

Inspection & Ownership

Last InspectionMarch 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number016086700000000

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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