US Bridges

FM over Dd

FairPosted for load

Humboldt County, Iowa · 092301102 · Structure no. 000000000184910

Built
1948
77 years old, rebuilt 1974
Condition
Fair
inspected November 2024
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
25 ft
1 main span
Daily traffic
34
2022 count
Owner
County
County Highway Agency

About this bridge

FM over Dd is a wood or timber stringer/multi-beam or girder carrying FM over Dd in Humboldt County, Iowa. It was built in 1948 and reconstructed in 1974, so it is 77 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 34 vehicles a day, projected to reach 34 by 2044. The structure is 25 ft (7.6 m) long and 22 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesFM
CrossesDd
Location092301102
RouteCounty Highway 0
CountyHumboldt County
StateIowa
Coordinates42.79883, -94.3644
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionNovember 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment9: Superior to present desirable criteria
Operating rating41.1 US tons
Inventory rating29.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans1
Design loadHS 20
Structure length25 ft (7.6 m)
Longest span23 ft (7 m)
Deck width22 ft (6.7 m)
Roadway width22 ft (6.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic34 (2022)
Projected traffic34 by 2044
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 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 FM over Dd built?

It was built in 1948, making it 77 years old in 2025. It was reconstructed in 1974.

What condition is FM over Dd 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 November 2024.

How much traffic does FM over Dd carry?

About 34 vehicles per day (2022 count).

How long is FM over Dd?

The structure is 25 ft (7.6 m) long with a longest span of 23 ft (7 m) and a deck 22 ft wide.

Who owns FM over Dd?

It is owned by the County Highway Agency.