Structure 19640 · Minidoka County, ID

Stc2866;baseline R over Snake R.(montgomery Br)

Carries Stc2866;baseline R over Snake R.(montgomery Br), 4.0 E. Rupert.

Overall conditionPoor

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

How ratings work
Deck6/9 · Satisfactory
Superstructure6/9 · Satisfactory
Substructuresets the rating4/9 · Poor
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT960 FT OVERALL200 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 6/9Substructure 4/9 · sets the rating

960 ft end to end, longest span 39 ft: about 2.7 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 tee-beam bridge.

Built1954rebuilt 1985
Length960.0 ft292.6 m
Daily traffic1,500counted 2023
Last inspectedSeptember 2024every 24 months

Location

StateIdaho
CountyMinidoka
Location4.0 E. Rupert
CarriesStc2866;baseline R
CrossesSnake R.(montgomery Br)
Coordinates42.61961, -113.58956

Physical Characteristics

MaterialConcrete
DesignTee Beam
Total Length960.0 ft (292.6 m)
Max Span39.0 ft (11.9 m)
Deck Width32.8 ft (10 m)
Deck Area2,926 sq m
Main Spans24
Year Built1954 (reconstructed 1985)

Traffic

Avg Daily Traffic1,500 (2023)
Truck Traffic8%
Lanes On Bridge2

Inspection & Ownership

Last InspectionSeptember 2024
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceHistorical significance is not determined
Scour Critical3 — Scour critical
Structure Number000000000019640

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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