Structure 12036 · Jefferson County, MO

Is 55 S over Rock CR

Carries Is 55 S over Rock CR, S 2024 T 42 N R 6 E.

Overall conditionGood

Set by its lowest-rated component: Deck and Superstructure at 7 of 9.

How ratings work
Decksets the rating7/9 · Good
Superstructuresets the rating7/9 · Good
Substructure8/9 · Very Good
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT198 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9 · sets the ratingSuperstructure 7/9 · sets the ratingSubstructure 8/9

198 ft end to end, longest span 75 ft: about 3 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.

Built200125 years old
Length198.2 ft60.4 m
Daily traffic53,723counted 2024
Last inspectedNovember 2024every 24 months

Location

StateMissouri
CountyJefferson
LocationS 2024 T 42 N R 6 E
CarriesIs 55 S
CrossesRock CR
Coordinates38.37467, -90.38019

Physical Characteristics

MaterialPrestressed Concrete Continuous
DesignStringer/Multi-beam
Total Length198.2 ft (60.4 m)
Max Span75.1 ft (22.9 m)
Deck Width81.0 ft (24.7 m)
Deck Area1491.9 sq m
Main Spans3
Year Built2001

Traffic

Avg Daily Traffic53,723 (2024)
Truck Traffic18%
Lanes On Bridge5

Inspection & Ownership

Last InspectionNovember 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number12036

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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