Structure 5090279 · Bon Homme County, SD

Sd037 over Missouri River

Carries Sd037 over Missouri River, 1.5ne Niobrara.

Overall conditionPoor

Set by its lowest-rated component: Substructure at 4 of 9.

How ratings work
Deck7/9 · Good
Superstructure8/9 · Very Good
Substructuresets the rating4/9 · Poor
Channelnot part of overall4/9 · Poor
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT2,953 FT OVERALL500 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 8/9Substructure 4/9 · sets the rating

2,953 ft end to end, longest span 185 ft: about 8.2 football fields. 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.

Built199630 years old
Length2953.1 ft900.1 m
Daily traffic830counted 2023
Last inspectedOctober 2024every 24 months

Location

StateSouth Dakota
CountyBon Homme
Location1.5ne Niobrara
CarriesSd037
CrossesMissouri River
Coordinates42.76941, -97.98957

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length2953.1 ft (900.1 m)
Max Span185.0 ft (56.4 m)
Deck Width37.7 ft (11.5 m)
Deck Area10351.1 sq m
Main Spans16
Year Built1996

Traffic

Avg Daily Traffic830 (2023)
Truck Traffic11%
Lanes On Bridge2

Inspection & Ownership

Last InspectionOctober 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical4 — Foundations need monitoring
Structure Number000000005090279

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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