Structure 3612 · Jefferson County, MO

Mo 21 S over Cotter CR

Carries Mo 21 S over Cotter CR, S 22 T 40 N R 4 W.

Overall conditionFair

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

How ratings work
Deck7/9 · Good
Superstructure7/9 · Good
Substructuresets the rating6/9 · Satisfactory
Channelnot part of overall5/9 · Fair
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT199 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 6/9 · sets the rating

199 ft end to end, longest span 67 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.

Built198937 years old
Length199.1 ft60.7 m
Daily traffic13,304counted 2024
Last inspectedDecember 2024every 24 months

Location

StateMissouri
CountyJefferson
LocationS 22 T 40 N R 4 W
CarriesMo 21 S
CrossesCotter CR
Coordinates38.18355, -90.56142

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length199.1 ft (60.7 m)
Max Span66.6 ft (20.3 m)
Deck Width41.3 ft (12.6 m)
Deck Area764.8 sq m
Main Spans3
Year Built1989

Traffic

Avg Daily Traffic13,304 (2024)
Truck Traffic7%
Lanes On Bridge2

Inspection & Ownership

Last InspectionDecember 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number3612

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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