Structure U05211000+01071 · Cascade County, MT

9th ST N over Missouri River

Carries 9th ST N over Missouri River, Great Falls-9th-10 ST N.

Overall conditionFair

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

How ratings work
Decksets the rating6/9 · Satisfactory
Superstructure8/9 · Very Good
Substructure7/9 · Good
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT1,232 FT OVERALL250 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 8/9Substructure 7/9

1,232 ft end to end, longest span 124 ft: about 3.4 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.

Built199630 years old
Length1232.3 ft375.6 m
Daily traffic14,024counted 2023
Last inspectedJuly 2024every 24 months

Location

StateMontana
CountyCascade
LocationGreat Falls-9th-10 ST N
Carries9th ST N
CrossesMissouri River
Coordinates47.52069, -111.29111

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length1232.3 ft (375.6 m)
Max Span123.7 ft (37.7 m)
Deck Width65.6 ft (20 m)
Deck Area7,512 sq m
Main Spans10
Year Built1996

Traffic

Avg Daily Traffic14,024 (2023)
Truck Traffic1%
Lanes On Bridge4

Inspection & Ownership

Last InspectionJuly 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure NumberU05211000+01071

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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