US Bridges

R70/580th Ave over Skunk River

FairPosted for load

Story County, Iowa · 082230904 · Structure no. 000000000314071

Built
1989
36 years old
Condition
Fair
inspected January 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
332 ft
4 main spans
Daily traffic
820
2023 count
Owner
County
County Highway Agency

About this bridge

R70/580th Ave over Skunk River is a prestressed concrete stringer/multi-beam or girder carrying R70/580th Ave over Skunk River in Story County, Iowa. It was built in 1989, so it is 36 years old, younger than the Iowa average of 45.5 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. Its operating status is: posted for load restriction.

It carries about 820 vehicles a day, projected to reach 820 by 2043. The structure is 332 ft (101.2 m) long and 32 ft wide. If it were closed, the detour would be 11.8 mi (19 km).

Location

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CarriesR70/580th Ave
CrossesSkunk River
Location082230904
RouteCounty Highway 0
CountyStory County
StateIowa
Coordinates41.93459, -93.54115
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJanuary 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating93.6 US tons
Inventory rating40.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length332 ft (101.2 m)
Longest span82 ft (25 m)
Deck width32 ft (9.8 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic820 (2023)
Projected traffic820 by 2043
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed11.8 mi (19 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was R70/580th Ave over Skunk River built?

It was built in 1989, making it 36 years old in 2025.

What condition is R70/580th Ave over Skunk 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 January 2023.

How much traffic does R70/580th Ave over Skunk River carry?

About 820 vehicles per day (2023 count).

How long is R70/580th Ave over Skunk River?

The structure is 332 ft (101.2 m) long with a longest span of 82 ft (25 m) and a deck 32 ft wide.

Who owns R70/580th Ave over Skunk River?

It is owned by the County Highway Agency.