US Bridges

Forest Grove RD over S Fork Mcdonald CR 046

FairPosted for load

Fergus County, Montana · 6M SW Grassrange · Structure no. L14202018+00001

Built
1986
39 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
32 ft
1 main span
Daily traffic
120
2023 count
Owner
County
County Highway Agency

About this bridge

Forest Grove RD over S Fork Mcdonald CR 046 is a wood or timber stringer/multi-beam or girder carrying Forest Grove RD over S Fork Mcdonald CR 046 in Fergus County, Montana. It was built in 1986, so it is 39 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 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 120 vehicles a day, roughly 3% of them trucks, projected to reach 127 by 2043. The structure is 32 ft (9.8 m) long and 20 ft wide. If it were closed, the detour would be 14.3 mi (23 km).

Location

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CarriesForest Grove RD
CrossesS Fork Mcdonald CR 046
Location6M SW Grassrange
RouteCounty Highway 14202
CountyFergus County
StateMontana
Coordinates46.99003, -108.92079
Functional classRural Minor Collector

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
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 rating17 US tons
Inventory rating13 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans1
Design loadUnknown
Structure length32 ft (9.8 m)
Longest span30 ft (9.1 m)
Deck width20 ft (6.2 m)
Roadway width20 ft (6.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic120 (2023)
Projected traffic127 by 2043
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed14.3 mi (23 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 Forest Grove RD over S Fork Mcdonald CR 046 built?

It was built in 1986, making it 39 years old in 2025.

What condition is Forest Grove RD over S Fork Mcdonald CR 046 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 2023.

How much traffic does Forest Grove RD over S Fork Mcdonald CR 046 carry?

About 120 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is Forest Grove RD over S Fork Mcdonald CR 046?

The structure is 32 ft (9.8 m) long with a longest span of 30 ft (9.1 m) and a deck 20 ft wide.

Who owns Forest Grove RD over S Fork Mcdonald CR 046?

It is owned by the County Highway Agency.