US Bridges

I-15 (SR-15) Sbl over Union Pacific Railroad

Fair

Box Elder County, Utah · 2 Mi.So.Plymouth Interchg · Structure no. 3F 481

Built
1990
35 years old
Condition
Fair
inspected April 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
177 ft
3 main spans
Daily traffic
13,856
2023 count
Owner
State
State Highway Agency

About this bridge

I-15 (SR-15) Sbl over Union Pacific Railroad is a prestressed concrete continuous stringer/multi-beam or girder carrying I-15 (SR-15) Sbl over Union Pacific Railroad in Box Elder County, Utah. It was built in 1990, so it is 35 years old, younger than the Utah average of 40.1 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 13,856 vehicles a day, roughly 41% of them trucks, projected to reach 16,627 by 2043. The structure is 177 ft (53.8 m) long and 46 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-15 (SR-15) Sbl
CrossesUnion Pacific Railroad
Location2 Mi.So.Plymouth Interchg
RouteInterstate 15
CountyBox Elder County
StateUtah
Coordinates41.86, -112.17028
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating63.9 US tons
Inventory rating39.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length177 ft (53.8 m)
Longest span79 ft (24.1 m)
Deck width46 ft (14 m)
Roadway width43 ft (13 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,856 (2023)
Projected traffic16,627 by 2043
Trucks41%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesRailroad
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-15 (SR-15) Sbl over Union Pacific Railroad built?

It was built in 1990, making it 35 years old in 2025.

What condition is I-15 (SR-15) Sbl over Union Pacific Railroad 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 I-15 (SR-15) Sbl over Union Pacific Railroad carry?

About 13,856 vehicles per day (2023 count), of which roughly 41% are trucks.

How long is I-15 (SR-15) Sbl over Union Pacific Railroad?

The structure is 177 ft (53.8 m) long with a longest span of 79 ft (24.1 m) and a deck 46 ft wide.

Who owns I-15 (SR-15) Sbl over Union Pacific Railroad?

It is owned by the State Highway Agency.