US Bridges

9th ST N over Missouri River

Fair

Cascade County, Montana · Great FALLS-9th-10 ST N · Structure no. U05211000+01071

Built
1996
29 years old
Condition
Fair
inspected July 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
1,232 ft
10 main spans
Daily traffic
14,024
2023 count
Owner
State
State Highway Agency

About this bridge

9th ST N over Missouri River is a prestressed concrete stringer/multi-beam or girder carrying 9th ST N over Missouri River in Cascade County, Montana. It was built in 1996, so it is 29 years old, younger than the Montana average of 47 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 14,024 vehicles a day, roughly 1% of them trucks, projected to reach 14,725 by 2043. The structure is 1,232 ft (375.6 m) long and 66 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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Carries9th ST N
CrossesMissouri River
LocationGreat FALLS-9th-10 ST N
RouteCity Street 104
CountyCascade County
StateMontana
Coordinates47.52069, -111.29111
Functional classUrban Other Principal Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure8 Very GoodNo problems noted.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating54 US tons
Inventory rating39 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans10
Design loadHS 20
Structure length1,232 ft (375.6 m)
Longest span124 ft (37.7 m)
Deck width66 ft (20 m)
Roadway width52 ft (15.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic14,024 (2023)
Projected traffic14,725 by 2043
Trucks1%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was 9th ST N over Missouri River built?

It was built in 1996, making it 29 years old in 2025.

What condition is 9th ST N over Missouri River in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in July 2024.

How much traffic does 9th ST N over Missouri River carry?

About 14,024 vehicles per day (2023 count), of which roughly 1% are trucks.

How long is 9th ST N over Missouri River?

The structure is 1,232 ft (375.6 m) long with a longest span of 124 ft (37.7 m) and a deck 66 ft wide.

Who owns 9th ST N over Missouri River?

It is owned by the State Highway Agency.