Structure 18130202 · Davison County, SD

407th Avenue over North Br Twelve Mile Ck

Carries 407th Avenue over North Br Twelve Mile Ck, 2 W & 10.2s Mitchell.

Overall conditionPoor

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

How ratings work
Deck5/9 · Fair
Superstructure5/9 · Fair
Substructuresets the rating4/9 · Poor
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT35 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9Superstructure 5/9Substructure 4/9 · sets the rating

35 ft end to end. 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 multi-beam bridge.

Built193096 years old
Length35.1 ft10.7 m
Daily traffic64counted 2022
Last inspectedAugust 2024every 24 months

Location

StateSouth Dakota
CountyDavison
Location2 W & 10.2s Mitchell
Carries407th Avenue
CrossesNorth Br Twelve Mile Ck
Coordinates43.55564, -98.06538

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length35.1 ft (10.7 m)
Max Span30.8 ft (9.4 m)
Deck Width18.0 ft (5.5 m)
Deck Area58.9 sq m
Main Spans1
Year Built1930

Traffic

Avg Daily Traffic64 (2022)
Truck Traffic2%
Lanes On Bridge2

Inspection & Ownership

Last InspectionAugust 2024
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is eligible for the National Register
Scour CriticalUnknown
Structure Number000000018130202

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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