US Bridges

I-25 Nbl and Sbl over Alkali Creek

Fair

Converse County, Wyoming · Douglas - Casper · Structure no. AGL

Built
1958
67 years old
Condition
Fair
inspected April 2023
Type
Culvert
Concrete Continuous
Length
21 ft
2 main spans
Daily traffic
4,607
2024 count
Owner
State
State Highway Agency

About this bridge

I-25 Nbl and Sbl over Alkali Creek is a concrete continuous culvert carrying I-25 Nbl and Sbl over Alkali Creek in Converse County, Wyoming. It was built in 1958, so it is 67 years old, older than the Wyoming average of 48.4 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 4,607 vehicles a day, roughly 20% of them trucks, projected to reach 6,450 by 2043. The structure is 21 ft (6.3 m) long. If it were closed, the detour would be 14.3 mi (23 km).

Location

Open in Google Maps
CarriesI-25 Nbl and Sbl
CrossesAlkali Creek
LocationDouglas - Casper
RouteInterstate 25
CountyConverse County
StateWyoming
Coordinates42.7936, -105.58672
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
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating36 US tons
Inventory rating36 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadUnknown
Structure length21 ft (6.3 m)
Longest span10 ft (3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,607 (2024)
Projected traffic6,450 by 2043
Trucks20%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed14.3 mi (23 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—
NavigationNo navigation control on waterway

Frequently asked questions

When was I-25 Nbl and Sbl over Alkali Creek built?

It was built in 1958, making it 67 years old in 2025.

What condition is I-25 Nbl and Sbl over Alkali 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 April 2023.

How much traffic does I-25 Nbl and Sbl over Alkali Creek carry?

About 4,607 vehicles per day (2024 count), of which roughly 20% are trucks.

How long is I-25 Nbl and Sbl over Alkali Creek?

The structure is 21 ft (6.3 m) long with a longest span of 10 ft (3 m).

Who owns I-25 Nbl and Sbl over Alkali Creek?

It is owned by the State Highway Agency.