Structure 68129205 · Yankton County, SD

Sd050 over Marne Ck

Carries Sd050 over Marne Ck, 0.8 E Jct US 81.

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 overall4/9 · Poor
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT119 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 6/9 · sets the rating

119 ft end to end, longest span 43 ft. Lengths and the car 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 slab bridge.

Built197155 years old
Length119.1 ft36.3 m
Daily traffic9,753counted 2024
Last inspectedFebruary 2025every 24 months

Location

StateSouth Dakota
CountyYankton
Location0.8 E Jct US 81
CarriesSd050
CrossesMarne Ck
Coordinates42.87179, -97.38121

Physical Characteristics

MaterialConcrete Continuous
DesignSlab
Total Length119.1 ft (36.3 m)
Max Span42.7 ft (13 m)
Deck Width55.1 ft (16.8 m)
Deck Area609.8 sq m
Main Spans3
Year Built1971

Traffic

Avg Daily Traffic9,753 (2024)
Truck Traffic7%
Lanes On Bridge4

Inspection & Ownership

Last InspectionFebruary 2025
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical7 — Countermeasures installed
Structure Number000000068129205

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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