US Bridges

US 30 over Portneuf River

Fair

Bannock County, Idaho · At Lava Hot Springs Ecl · Structure no. 000000000013715

Built
1977
48 years old
Condition
Fair
inspected October 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
255 ft
3 main spans
Daily traffic
4,300
2023 count
Owner
State
State Highway Agency

About this bridge

US 30 over Portneuf River is a prestressed concrete stringer/multi-beam or girder carrying US 30 over Portneuf River in Bannock County, Idaho. It was built in 1977, so it is 48 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 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 4,300 vehicles a day, roughly 20% of them trucks, projected to reach 6,450 by 2042. The structure is 255 ft (77.7 m) long and 53 ft wide. If it were closed, the detour would be 26.1 mi (42 km).

Location

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CarriesUS 30
CrossesPortneuf River
LocationAt Lava Hot Springs Ecl
RouteU.S. Route 30
CountyBannock County
StateIdaho
Coordinates42.62292, -111.99633
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionOctober 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 geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating49.1 US tons
Inventory rating29 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length255 ft (77.7 m)
Longest span122 ft (37.2 m)
Deck width53 ft (16.3 m)
Roadway width51 ft (15.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,300 (2023)
Projected traffic6,450 by 2042
Trucks20%
Lanes on structure3
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed26.1 mi (42 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$4.4 million (2017 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was US 30 over Portneuf River built?

It was built in 1977, making it 48 years old in 2025.

What condition is US 30 over Portneuf 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 October 2023.

How much traffic does US 30 over Portneuf River carry?

About 4,300 vehicles per day (2023 count), of which roughly 20% are trucks.

How long is US 30 over Portneuf River?

The structure is 255 ft (77.7 m) long with a longest span of 122 ft (37.2 m) and a deck 53 ft wide.

Who owns US 30 over Portneuf River?

It is owned by the State Highway Agency.