US Bridges

S 84-NORRIS RD over Gallatin River

Fair

Gallatin County, Montana · 7M W Bozeman · Structure no. P00084027+09401

Built
1987
38 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
152 ft
2 main spans
Daily traffic
10,845
2023 count
Owner
State
State Highway Agency

About this bridge

S 84-NORRIS RD over Gallatin River is a prestressed concrete stringer/multi-beam or girder carrying S 84-NORRIS RD over Gallatin River in Gallatin County, Montana. It was built in 1987, so it is 38 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 10,845 vehicles a day, roughly 1% of them trucks, projected to reach 12,743 by 2043. The structure is 152 ft (46.3 m) long and 41 ft wide. If it were closed, the detour would be 70.2 mi (113 km).

Location

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CarriesS 84-NORRIS RD
CrossesGallatin River
Location7M W Bozeman
RouteState Highway 84
CountyGallatin County
StateMontana
Coordinates45.67188, -111.20906
Functional classRural Minor 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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating51 US tons
Inventory rating27 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length152 ft (46.3 m)
Longest span76 ft (23.1 m)
Deck width41 ft (12.6 m)
Roadway width39 ft (12 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10,845 (2023)
Projected traffic12,743 by 2043
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed70.2 mi (113 km)
TollOn a free road
National Highway SystemNo

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 S 84-NORRIS RD over Gallatin River built?

It was built in 1987, making it 38 years old in 2025.

What condition is S 84-NORRIS RD over Gallatin 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 August 2023.

How much traffic does S 84-NORRIS RD over Gallatin River carry?

About 10,845 vehicles per day (2023 count), of which roughly 1% are trucks.

How long is S 84-NORRIS RD over Gallatin River?

The structure is 152 ft (46.3 m) long with a longest span of 76 ft (23.1 m) and a deck 41 ft wide.

Who owns S 84-NORRIS RD over Gallatin River?

It is owned by the State Highway Agency.