US Bridges

S Frontage RD W over Clark Fork 053

Poor

Mineral County, Montana · 2M W Alberton · Structure no. L31089001+04001

Built
1916
109 years old, rebuilt 1999
Condition
Poor
inspected June 2023
Type
Truss - Thru
Steel
Length
371 ft
2 main spans
Daily traffic
174
2023 count
Owner
County
County Highway Agency

About this bridge

S Frontage RD W over Clark Fork 053 is a steel truss - thru carrying S Frontage RD W over Clark Fork 053 in Mineral County, Montana. It was built in 1916 and reconstructed in 1999, so it is 109 years old, older than the Montana average of 47 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 174 vehicles a day, roughly 3% of them trucks, projected to reach 186 by 2043. The structure is 371 ft (113.1 m) long and 16 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesS Frontage RD W
CrossesClark Fork 053
Location2M W Alberton
RouteCounty Highway 31089
CountyMineral County
StateMontana
Coordinates47.01401, -114.50756
Functional classRural Local

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating42 US tons
Inventory rating25 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckWood or timber
Main spans2 (+2 approach)
Design loadUnknown
Structure length371 ft (113.1 m)
Longest span175 ft (53.3 m)
Deck width16 ft (4.9 m)
Roadway width16 ft (4.8 m)
Vertical clearance over deck13 ft (3.8 m)

Traffic and service

Average daily traffic174 (2023)
Projected traffic186 by 2043
Trucks3%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty 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 Frontage RD W over Clark Fork 053 built?

It was built in 1916, making it 109 years old in 2025. It was reconstructed in 1999.

What condition is S Frontage RD W over Clark Fork 053 in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in June 2023.

How much traffic does S Frontage RD W over Clark Fork 053 carry?

About 174 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is S Frontage RD W over Clark Fork 053?

The structure is 371 ft (113.1 m) long with a longest span of 175 ft (53.3 m) and a deck 16 ft wide.

Who owns S Frontage RD W over Clark Fork 053?

It is owned by the County Highway Agency.