US Bridges

SH 31 over Pine Creek

Fair

Bonneville County, Idaho · 5 N. Swan Valley · Structure no. 000000000013835

Built
1938
87 years old, rebuilt 2020
Condition
Fair
inspected September 2023
Type
Truss - Deck
Steel
Length
532 ft
1 main span
Daily traffic
2,700
2023 count
Owner
State
State Highway Agency

About this bridge

SH 31 over Pine Creek is a steel truss - deck carrying SH 31 over Pine Creek in Bonneville County, Idaho. It was built in 1938 and reconstructed in 2020, so it is 87 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 2,700 vehicles a day, roughly 11% of them trucks, projected to reach 4,050 by 2042. The structure is 532 ft (162.2 m) long and 31 ft wide. If it were closed, the detour would be 60.3 mi (97 km).

Location

Open in Google Maps
CarriesSH 31
CrossesPine Creek
Location5 N. Swan Valley
RouteState Highway 31
CountyBonneville County
StateIdaho
Coordinates43.50911, -111.35236
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations on dry land well above flood water elevations
Structural evaluation6: Equal to present minimum criteria
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 rating66 US tons
Inventory rating39 US tons

Structure

Structure typeTruss - Deck
MaterialSteel
DeckConcrete, cast-in-place
Main spans1 (+5 approach)
Design loadHS 20
Structure length532 ft (162.2 m)
Longest span290 ft (88.4 m)
Deck width31 ft (9.3 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,700 (2023)
Projected traffic4,050 by 2042
Trucks11%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed60.3 mi (97 km)
TollOn a free road
National Highway SystemNo

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$6.4 million (2020 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was SH 31 over Pine Creek built?

It was built in 1938, making it 87 years old in 2025. It was reconstructed in 2020.

What condition is SH 31 over Pine Creek 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 SH 31 over Pine Creek carry?

About 2,700 vehicles per day (2023 count), of which roughly 11% are trucks.

How long is SH 31 over Pine Creek?

The structure is 532 ft (162.2 m) long with a longest span of 290 ft (88.4 m) and a deck 31 ft wide.

Who owns SH 31 over Pine Creek?

It is owned by the State Highway Agency.