Structure 82300700000000 · St. Clair County, IL

Fau 9175 over Rock Spring Branch

Carries Fau 9175 over Rock Spring Branch, 0.5m N US 50.

Overall conditionFair

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

How ratings work
Deck7/9 · Good
Superstructuresets the rating6/9 · Satisfactory
Substructure7/9 · Good
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT143 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 6/9 · sets the ratingSubstructure 7/9

143 ft end to end, longest span 51 ft. 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.

Built197254 years old
Length142.7 ft43.5 m
Daily traffic11,400counted 2023
Last inspectedMarch 2024every 24 months

Location

StateIllinois
CountySt. Clair
Location0.5m N US 50
CarriesFau 9175
CrossesRock Spring Branch
Coordinates38.58853, -89.87408

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length142.7 ft (43.5 m)
Max Span50.9 ft (15.5 m)
Deck Width45.9 ft (14 m)
Deck Area609 sq m
Main Spans3
Year Built1972

Traffic

Avg Daily Traffic11,400 (2023)
Truck Traffic8%
Lanes On Bridge2

Inspection & Ownership

Last InspectionMarch 2024
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number082300700000000

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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