US Bridges

I 15 Sbl over Stc 6731;W 145 N Ic

Fair

Bonneville County, Idaho · 7.0 S. Roberts · Structure no. 000000000011805

Built
1962
63 years old
Condition
Fair
inspected March 2023
Type
Stringer/Multi-beam or Girder
Concrete
Length
108 ft
3 main spans
Daily traffic
3,200
2023 count
Owner
State
State Highway Agency

About this bridge

I 15 Sbl over Stc 6731;W 145 N Ic is a concrete stringer/multi-beam or girder carrying I 15 Sbl over Stc 6731;W 145 N Ic in Bonneville County, Idaho. It was built in 1962, so it is 63 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 3,200 vehicles a day, roughly 25% of them trucks, projected to reach 4,800 by 2042. The structure is 108 ft (32.9 m) long and 40 ft wide.

Location

Open in Google Maps
CarriesI 15 Sbl
CrossesStc 6731;W 145 N Ic
Location7.0 S. Roberts
RouteInterstate 15
CountyBonneville County
StateIdaho
Coordinates43.62418, -112.07981
Functional classRural Principal Arterial - Interstate

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating55 US tons
Inventory rating33 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialConcrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length108 ft (32.9 m)
Longest span35 ft (10.7 m)
Deck width40 ft (12.2 m)
Roadway width38 ft (11.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,200 (2023)
Projected traffic4,800 by 2042
Trucks25%
Lanes on structure2
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed—
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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$1.5 million (2021 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I 15 Sbl over Stc 6731;W 145 N Ic built?

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

What condition is I 15 Sbl over Stc 6731;W 145 N Ic 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 March 2023.

How much traffic does I 15 Sbl over Stc 6731;W 145 N Ic carry?

About 3,200 vehicles per day (2023 count), of which roughly 25% are trucks.

How long is I 15 Sbl over Stc 6731;W 145 N Ic?

The structure is 108 ft (32.9 m) long with a longest span of 35 ft (10.7 m) and a deck 40 ft wide.

Who owns I 15 Sbl over Stc 6731;W 145 N Ic?

It is owned by the State Highway Agency.