Structure I00090081+08401 · Missoula County, MT

I 90 over Clark Fork River

Carries I 90 over Clark Fork River, 6.2m E Alberton.

Overall conditionPoor

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

How ratings work
Decksets the rating4/9 · Poor
Superstructure5/9 · Fair
Substructure6/9 · Satisfactory
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT982 FT OVERALL200 FT0ELEVATION · LENGTHS TO SCALE
Deck 4/9 · sets the ratingSuperstructure 5/9Substructure 6/9

982 ft end to end, longest span 160 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 girder bridge.

Built196462 years old
Length981.6 ft299.2 m
Daily traffic9,168counted 2023
Last inspectedMarch 2024every 24 months

Location

StateMontana
CountyMissoula
Location6.2m E Alberton
CarriesI 90
CrossesClark Fork River
Coordinates47.02203, -114.38354

Physical Characteristics

MaterialSteel Continuous
DesignGirder and Floorbeam
Total Length981.6 ft (299.2 m)
Max Span160.1 ft (48.8 m)
Deck Width63.6 ft (19.4 m)
Deck Area5804.5 sq m
Main Spans4
Year Built1964

Traffic

Avg Daily Traffic9,168 (2023)
Truck Traffic20%
Lanes On Bridge4

Inspection & Ownership

Last InspectionMarch 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure NumberI00090081+08401

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.

Nearby Bridges