Structure 10705 · Power County, ID

I 86 Ebl over Rock Cr;massacre Rock Br

Carries I 86 Ebl over Rock Cr;massacre Rock Br, 12.1 W. American Falls.

Overall conditionFair

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

How ratings work
Deck8/9 · Very Good
Superstructure7/9 · Good
Substructuresets the rating6/9 · Satisfactory
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT178 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 8/9Superstructure 7/9Substructure 6/9 · sets the rating

178 ft end to end, longest span 58 ft: about 2 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.

Built198046 years old
Length178.1 ft54.3 m
Daily traffic4,150counted 2023
Last inspectedSeptember 2024every 48 months

Location

StateIdaho
CountyPower
Location12.1 W. American Falls
CarriesI 86 Ebl
CrossesRock Cr;massacre Rock Br
Coordinates42.65203, -113.01436

Physical Characteristics

MaterialPrestressed Concrete Continuous
DesignStringer/Multi-beam
Total Length178.1 ft (54.3 m)
Max Span58.1 ft (17.7 m)
Deck Width44.6 ft (13.6 m)
Deck Area738.5 sq m
Main Spans3
Year Built1980

Traffic

Avg Daily Traffic4,150 (2023)
Truck Traffic26%
Lanes On Bridge2

Inspection & Ownership

Last InspectionSeptember 2024
Inspection FrequencyEvery 48 months
OwnerState Highway Agency
Historical SignificanceHistorical significance is not determined
Scour Critical8 — Stable, low risk
Structure Number000000000010705

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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