US Bridges

S 135 over Clark Fork River

Fair

Sanders County, Montana · 11M SW Paradise · Structure no. P00035012+02581

Built
1962
63 years old
Condition
Fair
inspected September 2023
Type
Box Beam or Girders - Single or Spread
Concrete Continuous
Length
445 ft
4 main spans
Daily traffic
2,023
2023 count
Owner
State
State Highway Agency

About this bridge

S 135 over Clark Fork River is a concrete continuous box beam or girders - single or spread carrying S 135 over Clark Fork River in Sanders County, Montana. It was built in 1962, so it is 63 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 5 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 2,023 vehicles a day, roughly 7% of them trucks, projected to reach 2,124 by 2043. The structure is 445 ft (135.6 m) long and 31 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesS 135
CrossesClark Fork River
Location11M SW Paradise
RouteState Highway 135
CountySanders County
StateMontana
Coordinates47.32223, -114.89223
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
Deck7 GoodSome minor problems.
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 protection7 GoodSome minor problems.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating54 US tons
Inventory rating42 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialConcrete Continuous
DeckNot applicable
Main spans4
Design loadHS 20
Structure length445 ft (135.6 m)
Longest span125 ft (38.1 m)
Deck width31 ft (9.5 m)
Roadway width28 ft (8.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,023 (2023)
Projected traffic2,124 by 2043
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$861,000
NavigationNo navigation control on waterway

Frequently asked questions

When was S 135 over Clark Fork River built?

It was built in 1962, making it 63 years old in 2025.

What condition is S 135 over Clark Fork 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 September 2023.

How much traffic does S 135 over Clark Fork River carry?

About 2,023 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is S 135 over Clark Fork River?

The structure is 445 ft (135.6 m) long with a longest span of 125 ft (38.1 m) and a deck 31 ft wide.

Who owns S 135 over Clark Fork River?

It is owned by the State Highway Agency.