US Bridges

US 212 over Thompson Creek

Fair

Carter County, Montana · 3M NW Alzada · Structure no. P00023134+04021

Built
1965
60 years old
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
103 ft
2 main spans
Daily traffic
2,642
2023 count
Owner
State
State Highway Agency

About this bridge

US 212 over Thompson Creek is a prestressed concrete stringer/multi-beam or girder carrying US 212 over Thompson Creek in Carter County, Montana. It was built in 1965, so it is 60 years old, older 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 2,642 vehicles a day, roughly 30% of them trucks, projected to reach 2,959 by 2043. The structure is 103 ft (31.3 m) long and 40 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesUS 212
CrossesThompson Creek
Location3M NW Alzada
RouteU.S. Route 212
CountyCarter County
StateMontana
Coordinates45.0487, -104.45167
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure8 Very GoodNo problems noted.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 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 rating58 US tons
Inventory rating44 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length103 ft (31.3 m)
Longest span51 ft (15.5 m)
Deck width40 ft (12.3 m)
Roadway width38 ft (11.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,642 (2023)
Projected traffic2,959 by 2043
Trucks30%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 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 US 212 over Thompson Creek built?

It was built in 1965, making it 60 years old in 2025.

What condition is US 212 over Thompson Creek 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 September 2023.

How much traffic does US 212 over Thompson Creek carry?

About 2,642 vehicles per day (2023 count), of which roughly 30% are trucks.

How long is US 212 over Thompson Creek?

The structure is 103 ft (31.3 m) long with a longest span of 51 ft (15.5 m) and a deck 40 ft wide.

Who owns US 212 over Thompson Creek?

It is owned by the State Highway Agency.