US Bridges

STC6870;PAHSIMEROI over Pahsimeroi River

Fair

Lemhi County, Idaho · At Ellis · Structure no. 000000000021175

Built
1978
47 years old
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
90 ft
1 main span
Daily traffic
190
2023 count
Owner
County
County Highway Agency

About this bridge

STC6870;PAHSIMEROI over Pahsimeroi River is a prestressed concrete stringer/multi-beam or girder carrying STC6870;PAHSIMEROI over Pahsimeroi River in Lemhi County, Idaho. It was built in 1978, so it is 47 years old, older than the Idaho average of 45.3 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 190 vehicles a day, roughly 12% of them trucks, projected to reach 285 by 2042. The structure is 90 ft (27.4 m) long and 32 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesSTC6870;PAHSIMEROI
CrossesPahsimeroi River
LocationAt Ellis
RouteCounty Highway 6870
CountyLemhi County
StateIdaho
Coordinates44.69192, -114.04831
Functional classRural Major 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.
Superstructure8 Very GoodNo problems noted.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionApril 2023
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating73 US tons
Inventory rating38 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length90 ft (27.4 m)
Longest span86 ft (26.2 m)
Deck width32 ft (9.7 m)
Roadway width29 ft (8.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic190 (2023)
Projected traffic285 by 2042
Trucks12%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was STC6870;PAHSIMEROI over Pahsimeroi River built?

It was built in 1978, making it 47 years old in 2025.

What condition is STC6870;PAHSIMEROI over Pahsimeroi 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 April 2023.

How much traffic does STC6870;PAHSIMEROI over Pahsimeroi River carry?

About 190 vehicles per day (2023 count), of which roughly 12% are trucks.

How long is STC6870;PAHSIMEROI over Pahsimeroi River?

The structure is 90 ft (27.4 m) long with a longest span of 86 ft (26.2 m) and a deck 32 ft wide.

Who owns STC6870;PAHSIMEROI over Pahsimeroi River?

It is owned by the County Highway Agency.