Structure 4549 · Shelby County, AL

Al - 3 (us 31) over Cahaba River

Carries Al - 3 (us 31) over Cahaba River, @ Jefferson/shelby Cl.

Overall conditionFair

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

How ratings work
Decksets the rating5/9 · Fair
Superstructuresets the rating5/9 · Fair
Substructuresets the rating5/9 · Fair
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT466 FT OVERALL100 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9Superstructure 5/9Substructure 5/9

466 ft end to end, longest span 100 ft: about 6 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.

Built195373 years old
Length465.9 ft142 m
Daily traffic27,940counted 2024
Last inspectedJanuary 2024every 24 months

Location

StateAlabama
CountyShelby
Location@ Jefferson/shelby Cl
CarriesAl - 3 (us 31)
CrossesCahaba River
Coordinates33.36616, -86.79717

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length465.9 ft (142 m)
Max Span100.1 ft (30.5 m)
Deck Width59.1 ft (18 m)
Deck Area2,556 sq m
Main Spans3
Year Built1953

Traffic

Avg Daily Traffic27,940 (2024)
Truck Traffic4%
Lanes On Bridge4

Inspection & Ownership

Last InspectionJanuary 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number004549

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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