Structure I00015160+03461 · Jefferson County, MT

I 15 over Int High Ore

Carries I 15 over Int High Ore, 3.7m E Basin.

Overall conditionFair

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

How ratings work
Decksets the rating6/9 · Satisfactory
Superstructure7/9 · Good
Substructuresets the rating6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT133 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 7/9Substructure 6/9 · sets the rating

133 ft end to end, longest span 52 ft. 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.

Built198244 years old
Length132.9 ft40.5 m
Daily traffic3,856counted 2023
Last inspectedJanuary 2025every 24 months

Location

StateMontana
CountyJefferson
Location3.7m E Basin
CarriesI 15
CrossesInt High Ore
Coordinates46.26030, -112.19475

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length132.9 ft (40.5 m)
Max Span51.5 ft (15.7 m)
Deck Width98.1 ft (29.9 m)
Deck Area1211.0 sq m
Main Spans3
Year Built1982

Traffic

Avg Daily Traffic3,856 (2023)
Truck Traffic13%
Lanes On Bridge4
Lanes Under Bridge2

Inspection & Ownership

Last InspectionJanuary 2025
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure NumberI00015160+03461

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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