Structure 68003600000000 · Montgomery County, IL

Tr 17 over I-55

Carries Tr 17 over I-55, 3.05m S Sangamon Co..

Overall conditionPoor

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

How ratings work
Deck6/9 · Satisfactory
Superstructuresets the rating3/9 · Serious
Substructure6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT339 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 3/9 · sets the ratingSubstructure 6/9

339 ft end to end, longest span 109 ft: about 5 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.

Built197056 years old
Length338.9 ft103.3 m
Daily traffic50counted 2020
Last inspectedMay 2024every 12 months

Location

StateIllinois
CountyMontgomery
Location3.05m S Sangamon Co.
CarriesTr 17
CrossesI-55
Coordinates39.47987, -89.64557

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length338.9 ft (103.3 m)
Max Span108.9 ft (33.2 m)
Deck Width29.9 ft (9.1 m)
Deck Area940.0 sq m
Main Spans3
Year Built1970

Traffic

Avg Daily Traffic50 (2020)
Truck Traffic60%
Lanes On Bridge2
Lanes Under Bridge8

Inspection & Ownership

Last InspectionMay 2024
Inspection FrequencyEvery 12 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number068003600000000

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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