US Bridges

Wyo 256 over North Platte River

Fair

Natrona County, Wyoming · JCT US 20 2687 - North · Structure no. CSG

Built
1971
54 years old
Condition
Fair
inspected June 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
320 ft
3 main spans
Daily traffic
3,055
2024 count
Owner
State
State Highway Agency

About this bridge

Wyo 256 over North Platte River is a steel continuous stringer/multi-beam or girder carrying Wyo 256 over North Platte River in Natrona County, Wyoming. It was built in 1971, so it is 54 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 3,055 vehicles a day, roughly 7% of them trucks, projected to reach 4,277 by 2043. The structure is 320 ft (97.5 m) long and 35 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

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CarriesWyo 256
CrossesNorth Platte River
LocationJCT US 20 2687 - North
RouteState Highway 256
CountyNatrona County
StateWyoming
Coordinates42.85834, -106.212
Functional classRural Major 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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 2024
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 geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating99.6 US tons
Inventory rating59.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length320 ft (97.5 m)
Longest span124 ft (37.8 m)
Deck width35 ft (10.6 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,055 (2024)
Projected traffic4,277 by 2043
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Wyo 256 over North Platte River built?

It was built in 1971, making it 54 years old in 2025.

What condition is Wyo 256 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 June 2024.

How much traffic does Wyo 256 over North Platte River carry?

About 3,055 vehicles per day (2024 count), of which roughly 7% are trucks.

How long is Wyo 256 over North Platte River?

The structure is 320 ft (97.5 m) long with a longest span of 124 ft (37.8 m) and a deck 35 ft wide.

Who owns Wyo 256 over North Platte River?

It is owned by the State Highway Agency.