US Bridges

720th Ave over Willow Creek

FairPosted for load

Story County, Iowa · 082210202 · Structure no. 000000000313470

Built
1945
80 years old, rebuilt 1988
Condition
Fair
inspected February 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
39 ft
1 main span
Daily traffic
15
2022 count
Owner
County
County Highway Agency

About this bridge

720th Ave over Willow Creek is a steel stringer/multi-beam or girder carrying 720th Ave over Willow Creek in Story County, Iowa. It was built in 1945 and reconstructed in 1988, so it is 80 years old, older 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 5 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 15 vehicles a day, projected to reach 15 by 2043. The structure is 39 ft (11.9 m) long and 24 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
Carries720th Ave
CrossesWillow Creek
Location082210202
RouteCounty Highway 0
CountyStory County
StateIowa
Coordinates41.94801, -93.27054
Functional classRural Local

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.
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 protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating27.8 US tons
Inventory rating16.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckWood or timber
Main spans1
Design loadHS 20
Structure length39 ft (11.9 m)
Longest span37 ft (11.3 m)
Deck width24 ft (7.3 m)
Roadway width23 ft (7.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic15 (2022)
Projected traffic15 by 2043
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 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—
NavigationNo navigation control on waterway

Frequently asked questions

When was 720th Ave over Willow Creek built?

It was built in 1945, making it 80 years old in 2025. It was reconstructed in 1988.

What condition is 720th Ave over Willow 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 February 2023.

How much traffic does 720th Ave over Willow Creek carry?

About 15 vehicles per day (2022 count).

How long is 720th Ave over Willow Creek?

The structure is 39 ft (11.9 m) long with a longest span of 37 ft (11.3 m) and a deck 24 ft wide.

Who owns 720th Ave over Willow Creek?

It is owned by the County Highway Agency.