Structure 41092079 · Lawrence County, SD

Jackson BLVD over Spearfish Ck

Carries Jackson BLVD over Spearfish Ck, Jackson BLVD - Spearfish.

Overall conditionFair

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

How ratings work
Decksets the rating6/9 · Satisfactory
Superstructuresets the rating6/9 · Satisfactory
Substructuresets the rating6/9 · Satisfactory
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT72 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 6/9Substructure 6/9

72 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 box-beam bridge.

Built196660 years old
Length71.9 ft21.9 m
Daily traffic12,135counted 2022
Last inspectedOctober 2023every 24 months

Location

StateSouth Dakota
CountyLawrence
LocationJackson BLVD - Spearfish
CarriesJackson BLVD
CrossesSpearfish Ck
Coordinates44.49031, -103.86486

Physical Characteristics

MaterialPrestressed Concrete
DesignBox Beam - Multiple
Total Length71.9 ft (21.9 m)
Max Span68.9 ft (21 m)
Deck Width60.0 ft (18.3 m)
Deck Area400.8 sq m
Main Spans1
Year Built1966

Traffic

Avg Daily Traffic12,135 (2022)
Truck Traffic5%
Lanes On Bridge4

Inspection & Ownership

Last InspectionOctober 2023
Inspection FrequencyEvery 24 months
OwnerCity/Municipal Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number000000041092079

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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