Structure I00090022+00131 · Mineral County, MT

I 90 over Int Henderson

Carries I 90 over Int Henderson, 3.1m E De Borgia.

Overall conditionFair

Set by its lowest-rated component: Deck at 5 of 9.

How ratings work
Decksets the rating5/9 · Fair
Superstructure7/9 · Good
Substructure7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT138 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9 · sets the ratingSuperstructure 7/9Substructure 7/9

138 ft end to end, longest span 56 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.

Built1980rebuilt 2007
Length138.1 ft42.1 m
Daily traffic7,448counted 2023
Last inspectedMay 2023every 24 months

Location

StateMontana
CountyMineral
Location3.1m E De Borgia
CarriesI 90
CrossesInt Henderson
Coordinates47.35457, -115.29358

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length138.1 ft (42.1 m)
Max Span56.1 ft (17.1 m)
Deck Width91.2 ft (27.8 m)
Deck Area1170.4 sq m
Main Spans3
Year Built1980 (reconstructed 2007)

Traffic

Avg Daily Traffic7,448 (2023)
Truck Traffic26%
Lanes On Bridge4
Lanes Under Bridge2

Inspection & Ownership

Last InspectionMay 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure NumberI00090022+00131

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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