Structure CEPMROSD0000008 · Buffalo County, SD

State Highway 47 over Big Bend Dam Spillway

Carries State Highway 47 over Big Bend Dam Spillway, 1 Mi. So. Of Ft. Thompson.

Overall conditionFair

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

How ratings work
Decksets the rating6/9 · Satisfactory
Superstructuresets the rating6/9 · Satisfactory
Substructure7/9 · Good
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT135 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 6/9 · sets the ratingSubstructure 7/9

135 ft end to end, longest span 16 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 girder bridge.

Built196363 years old
Length134.8 ft41.1 m
Daily traffic676counted 2022
Last inspectedSeptember 2023every 24 months

Location

StateSouth Dakota
CountyBuffalo
Location1 Mi. So. Of Ft. Thompson
CarriesState Highway 47
CrossesBig Bend Dam Spillway
Coordinates44.06080, -99.45388

Physical Characteristics

MaterialSteel
DesignGirder and Floorbeam
Total Length134.8 ft (41.1 m)
Max Span16.1 ft (4.9 m)
Deck Width12.1 ft (3.7 m)
Deck Area152.1 sq m
Main Spans9
Year Built1963

Traffic

Avg Daily Traffic676 (2022)
Truck Traffic32%
Lanes On Bridge2

Inspection & Ownership

Last InspectionSeptember 2023
Inspection FrequencyEvery 24 months
OwnerCorps of Engineers
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure NumberCEPMROSD0000008

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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