Structure I00090066+02792 · Mineral County, MT

I 90 over Clark Fork River

Carries I 90 over Clark Fork River, 9.3m W Alberton.

Overall conditionPoor

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

How ratings work
Deck6/9 · Satisfactory
Superstructuresets the rating4/9 · Poor
Substructure6/9 · Satisfactory
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT807 FT OVERALL100 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 4/9 · sets the ratingSubstructure 6/9

807 ft end to end, longest span 210 ft: about 2.2 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 girder bridge.

Built196561 years old
Length806.8 ft245.9 m
Daily traffic4,088counted 2023
Last inspectedMay 2023every 24 months

Location

StateMontana
CountyMineral
Location9.3m W Alberton
CarriesI 90
CrossesClark Fork River
Coordinates47.01924, -114.65821

Physical Characteristics

MaterialSteel Continuous
DesignGirder and Floorbeam
Total Length806.8 ft (245.9 m)
Max Span210.0 ft (64 m)
Deck Width31.8 ft (9.7 m)
Deck Area2385.2 sq m
Main Spans3
Year Built1965

Traffic

Avg Daily Traffic4,088 (2023)
Truck Traffic23%
Lanes On Bridge2

Inspection & Ownership

Last InspectionMay 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure NumberI00090066+02792

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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