Structure 58001000000000 · Macon County, IL

US 51 NB (fap 710) over Lake Decatur

Carries US 51 NB (fap 710) over Lake Decatur, In Decatur.

Overall conditionFair

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

How ratings work
Deck6/9 · Satisfactory
Superstructuresets the rating5/9 · Fair
Substructure7/9 · Good
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT530 FT OVERALL100 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 5/9 · sets the ratingSubstructure 7/9

530 ft end to end, longest span 188 ft: about 7 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.

Built196264 years old
Length529.9 ft161.5 m
Daily traffic22,400counted 2023
Last inspectedJuly 2024every 24 months

Location

StateIllinois
CountyMacon
LocationIn Decatur
CarriesUS 51 NB (fap 710)
CrossesLake Decatur
Coordinates39.82576, -88.95542

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length529.9 ft (161.5 m)
Max Span188.0 ft (57.3 m)
Deck Width38.4 ft (11.7 m)
Deck Area1889.5 sq m
Main Spans3
Year Built1962

Traffic

Avg Daily Traffic22,400 (2023)
Truck Traffic5%
Lanes On Bridge2

Inspection & Ownership

Last InspectionJuly 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number058001000000000

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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