US Bridges

FM 400th ST over Willow Creek

Fair

Clay County, Iowa · 095380801 · Structure no. 000000000116390

Built
1968
57 years old
Condition
Fair
inspected December 2024
Type
Slab
Concrete Continuous
Length
75 ft
3 main spans
Daily traffic
797
2022 count
Owner
County
County Highway Agency

About this bridge

FM 400th ST over Willow Creek is a concrete continuous slab carrying FM 400th ST over Willow Creek in Clay County, Iowa. It was built in 1968, so it is 57 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.

It carries about 797 vehicles a day, roughly 24% of them trucks, projected to reach 797 by 2044. The structure is 75 ft (22.9 m) long and 32 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesFM 400th ST
CrossesWillow Creek
Location095380801
RouteCounty Highway 0
CountyClay County
StateIowa
Coordinates43.06878, -95.3681
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionDecember 2024
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
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating60.4 US tons
Inventory rating36 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 20
Structure length75 ft (22.9 m)
Longest span29 ft (8.8 m)
Deck width32 ft (9.8 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic797 (2022)
Projected traffic797 by 2044
Trucks24%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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 proposedOther structural work, including hydraulic replacements
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was FM 400th ST over Willow Creek built?

It was built in 1968, making it 57 years old in 2025.

What condition is FM 400th ST 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 December 2024.

How much traffic does FM 400th ST over Willow Creek carry?

About 797 vehicles per day (2022 count), of which roughly 24% are trucks.

How long is FM 400th ST over Willow Creek?

The structure is 75 ft (22.9 m) long with a longest span of 29 ft (8.8 m) and a deck 32 ft wide.

Who owns FM 400th ST over Willow Creek?

It is owned by the County Highway Agency.