US Bridges

I-15 (SR-15) Nb&sb over Mill Creek

Fair

Washington County, Utah · 0.6 MI No Washington Int. · Structure no. 0E1329

Built
1964
61 years old
Condition
Fair
inspected January 2023
Type
Culvert
Concrete Continuous
Length
27 ft
2 main spans
Daily traffic
64,174
2017 count
Owner
State
State Highway Agency

About this bridge

I-15 (SR-15) Nb&sb over Mill Creek is a concrete continuous culvert carrying I-15 (SR-15) Nb&sb over Mill Creek in Washington County, Utah. It was built in 1964, so it is 61 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 64,174 vehicles a day, roughly 23% of them trucks, projected to reach 77,009 by 2037. The structure is 27 ft (8.3 m) long. If it were closed, the detour would be 5 mi (8 km).

Location

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CarriesI-15 (SR-15) Nb&sb
CrossesMill Creek
Location0.6 MI No Washington Int.
RouteInterstate 15
CountyWashington County
StateUtah
Coordinates37.13388, -113.51726
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
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating107.1 US tons
Inventory rating106.5 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadHS 20
Structure length27 ft (8.3 m)
Longest span12 ft (3.7 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic64,174 (2017)
Projected traffic77,009 by 2037
Trucks23%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 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) Nb&sb over Mill Creek built?

It was built in 1964, making it 61 years old in 2025.

What condition is I-15 (SR-15) Nb&sb over Mill 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) Nb&sb over Mill Creek carry?

About 64,174 vehicles per day (2017 count), of which roughly 23% are trucks.

How long is I-15 (SR-15) Nb&sb over Mill Creek?

The structure is 27 ft (8.3 m) long with a longest span of 12 ft (3.7 m).

Who owns I-15 (SR-15) Nb&sb over Mill Creek?

It is owned by the State Highway Agency.