Structure 55176060 · Roberts County, SD

IRR I029 N over Sd127

Carries IRR I029 N over Sd127, Sd 127 & I29 Interchange.

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
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT221 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 6/9Substructure 6/9

221 ft end to end, longest span 92 ft: about 3 semi-trucks nose to tail. 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.

Built197650 years old
Length221.1 ft67.4 m
Daily traffic2,705counted 2024
Last inspectedMay 2023every 24 months

Location

StateSouth Dakota
CountyRoberts
LocationSd 127 & I29 Interchange
CarriesIRR I029 N
CrossesSd127
Coordinates45.84999, -96.86502

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length221.1 ft (67.4 m)
Max Span91.9 ft (28 m)
Deck Width42.7 ft (13 m)
Deck Area876.2 sq m
Main Spans3
Year Built1976

Traffic

Avg Daily Traffic2,705 (2024)
Truck Traffic42%
Lanes On Bridge2
Lanes Under Bridge2

Inspection & Ownership

Last InspectionMay 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number000000055176060

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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