US Bridges

I-15 (SR-15) Nbl over Co. Rd. Intchg. X-Road

Fair

Washington County, Utah · Black Ridge Interchange · Structure no. 1D 644

Built
1959
66 years old, rebuilt 2011
Condition
Fair
inspected January 2025
Type
Frame
Concrete
Length
31 ft
1 main span
Daily traffic
22,640
2014 count
Owner
State
State Highway Agency

About this bridge

I-15 (SR-15) Nbl over Co. Rd. Intchg. X-Road is a concrete frame carrying I-15 (SR-15) Nbl over Co. Rd. Intchg. X-Road in Washington County, Utah. It was built in 1959 and reconstructed in 2011, so it is 66 years old, older 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 22,640 vehicles a day, roughly 43% of them trucks, projected to reach 28,300 by 2034. The structure is 31 ft (9.4 m) long and 122 ft wide.

Location

Open in Google Maps
CarriesI-15 (SR-15) Nbl
CrossesCo. Rd. Intchg. X-Road
LocationBlack Ridge Interchange
RouteInterstate 15
CountyWashington County
StateUtah
Coordinates37.40507, -113.23786
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 inspectionJanuary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating46.4 US tons
Inventory rating28.5 US tons

Structure

Structure typeFrame
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length31 ft (9.4 m)
Longest span27 ft (8.2 m)
Deck width122 ft (37.2 m)
Roadway width56 ft (17.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic22,640 (2014)
Projected traffic28,300 by 2034
Trucks43%
Lanes on structure3
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 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) Nbl over Co. Rd. Intchg. X-Road built?

It was built in 1959, making it 66 years old in 2025. It was reconstructed in 2011.

What condition is I-15 (SR-15) Nbl over Co. Rd. Intchg. X-Road 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 January 2025.

How much traffic does I-15 (SR-15) Nbl over Co. Rd. Intchg. X-Road carry?

About 22,640 vehicles per day (2014 count), of which roughly 43% are trucks.

How long is I-15 (SR-15) Nbl over Co. Rd. Intchg. X-Road?

The structure is 31 ft (9.4 m) long with a longest span of 27 ft (8.2 m) and a deck 122 ft wide.

Who owns I-15 (SR-15) Nbl over Co. Rd. Intchg. X-Road?

It is owned by the State Highway Agency.