US Bridges

I-15 (SR-15) Nbl over Cottonwood Creek

Fair

Washington County, Utah · 3.5 Mi.No.Harrisburg Int. · Structure no. 1D 555

Built
1956
69 years old
Condition
Fair
inspected January 2023
Type
Frame
Concrete
Length
65 ft
1 main span
Daily traffic
30,540
2022 count
Owner
State
State Highway Agency

About this bridge

I-15 (SR-15) Nbl over Cottonwood Creek is a concrete frame carrying I-15 (SR-15) Nbl over Cottonwood Creek in Washington County, Utah. It was built in 1956, so it is 69 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 30,540 vehicles a day, roughly 26% of them trucks, projected to reach 36,648 by 2042. The structure is 65 ft (19.9 m) long and 65 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

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CarriesI-15 (SR-15) Nbl
CrossesCottonwood Creek
Location3.5 Mi.No.Harrisburg Int.
RouteInterstate 15
CountyWashington County
StateUtah
Coordinates37.19684, -113.40121
Functional classUrban 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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating44.6 US tons
Inventory rating32.8 US tons

Structure

Structure typeFrame
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length65 ft (19.9 m)
Longest span65 ft (19.9 m)
Deck width65 ft (19.8 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deck99 ft (30.2 m)

Traffic and service

Average daily traffic30,540 (2022)
Projected traffic36,648 by 2042
Trucks26%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed0.6 mi (1 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) Nbl over Cottonwood Creek built?

It was built in 1956, making it 69 years old in 2025.

What condition is I-15 (SR-15) Nbl over Cottonwood 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 January 2023.

How much traffic does I-15 (SR-15) Nbl over Cottonwood Creek carry?

About 30,540 vehicles per day (2022 count), of which roughly 26% are trucks.

How long is I-15 (SR-15) Nbl over Cottonwood Creek?

The structure is 65 ft (19.9 m) long with a longest span of 65 ft (19.9 m) and a deck 65 ft wide.

Who owns I-15 (SR-15) Nbl over Cottonwood Creek?

It is owned by the State Highway Agency.