US Bridges

RD 7688 over W Fk Fishtrap

Fair

Sanders County, Montana · Lower Fishtrap Ridg · Structure no. 011608000000169

Built
1965
60 years old
Condition
Fair
inspected October 2024
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
32 ft
1 main span
Daily traffic
40
Owner
Federal
U.S. Forest Service

About this bridge

RD 7688 over W Fk Fishtrap is a wood or timber stringer/multi-beam or girder carrying RD 7688 over W Fk Fishtrap in Sanders 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 40 vehicles a day, projected to reach 60 by 2045. The structure is 32 ft (9.9 m) long and 15 ft wide. If it were closed, the detour would be 98.2 mi (158 km).

Location

Open in Google Maps
CarriesRD 7688
CrossesW Fk Fishtrap
LocationLower Fishtrap Ridg
RouteFederal Lands Road 7688
CountySanders County
StateMontana
Coordinates47.81531, -115.1445
Functional classRural Local

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 protection8 Very GoodNo problems noted.
Last inspectionOctober 2024
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 adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating30.8 US tons
Inventory rating23.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans1
Design loadHS 20
Structure length32 ft (9.9 m)
Longest span31 ft (9.4 m)
Deck width15 ft (4.6 m)
Roadway width13 ft (4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic40 (—)
Projected traffic60 by 2045
Trucks—
Lanes on structure1
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.2 mi (158 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerU.S. Forest Service
Maintained byU.S. Forest Service
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was RD 7688 over W Fk Fishtrap built?

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

What condition is RD 7688 over W Fk Fishtrap 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 October 2024.

How much traffic does RD 7688 over W Fk Fishtrap carry?

About 40 vehicles per day (latest count).

How long is RD 7688 over W Fk Fishtrap?

The structure is 32 ft (9.9 m) long with a longest span of 31 ft (9.4 m) and a deck 15 ft wide.

Who owns RD 7688 over W Fk Fishtrap?

It is owned by the U.S. Forest Service.