US Bridges

Na Cnty RD 408 over North Platte River

Fair

Natrona County, Wyoming · 7.5 Miles S.W. of Alcova · Structure no. DUZ

Built
1957
68 years old
Condition
Fair
inspected September 2023
Type
Truss - Thru
Steel
Length
144 ft
1 main span
Daily traffic
84
2024 count
Owner
County
County Highway Agency

About this bridge

Na Cnty RD 408 over North Platte River is a steel truss - thru carrying Na Cnty RD 408 over North Platte River in Natrona County, Wyoming. It was built in 1957, so it is 68 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 84 vehicles a day, roughly 68% of them trucks, projected to reach 118 by 2043. The structure is 144 ft (43.9 m) long and 28 ft wide. If it were closed, the detour would be 23 mi (37 km).

Location

Open in Google Maps
CarriesNa Cnty RD 408
CrossesNorth Platte River
Location7.5 Miles S.W. of Alcova
RouteCounty Highway 408
CountyNatrona County
StateWyoming
Coordinates42.47089, -106.79611
Functional classRural Minor Collector

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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations on dry land well above flood water elevations
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating65 US tons
Inventory rating37 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length144 ft (43.9 m)
Longest span140 ft (42.7 m)
Deck width28 ft (8.6 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic84 (2024)
Projected traffic118 by 2043
Trucks68%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed23 mi (37 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$751,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Na Cnty RD 408 over North Platte River built?

It was built in 1957, making it 68 years old in 2025.

What condition is Na Cnty RD 408 over North Platte River 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 September 2023.

How much traffic does Na Cnty RD 408 over North Platte River carry?

About 84 vehicles per day (2024 count), of which roughly 68% are trucks.

How long is Na Cnty RD 408 over North Platte River?

The structure is 144 ft (43.9 m) long with a longest span of 140 ft (42.7 m) and a deck 28 ft wide.

Who owns Na Cnty RD 408 over North Platte River?

It is owned by the County Highway Agency.