Structure I00090042+09192 · Mineral County, MT

I 90 over Clark Fork River

Carries I 90 over Clark Fork River, 3.7m W Superior.

Overall conditionPoor

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

How ratings work
Decksets the rating4/9 · Poor
Superstructure5/9 · Fair
Substructure5/9 · Fair
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT1,092 FT OVERALL200 FT0ELEVATION · LENGTHS TO SCALE
Deck 4/9 · sets the ratingSuperstructure 5/9Substructure 5/9

1,092 ft end to end, longest span 198 ft: about 3.0 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 multi-beam bridge.

Built198442 years old
Length1091.9 ft332.8 m
Daily traffic3,719counted 2023
Last inspectedJune 2023every 24 months

Location

StateMontana
CountyMineral
Location3.7m W Superior
CarriesI 90
CrossesClark Fork River
Coordinates47.22092, -114.96120

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length1091.9 ft (332.8 m)
Max Span197.8 ft (60.3 m)
Deck Width44.0 ft (13.4 m)
Deck Area4459.5 sq m
Main Spans6
Year Built1984

Traffic

Avg Daily Traffic3,719 (2023)
Truck Traffic27%
Lanes On Bridge2

Inspection & Ownership

Last InspectionJune 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure NumberI00090042+09192

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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