US Bridges

FM over Dd

Poor

Hardin County, Iowa · 089210201 · Structure no. 000000000176660

Built
1971
54 years old
Condition
Poor
inspected February 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
68 ft
1 main span
Daily traffic
776
2022 count
Owner
County
County Highway Agency

About this bridge

FM over Dd is a prestressed concrete stringer/multi-beam or girder carrying FM over Dd in Hardin County, Iowa. It was built in 1971, so it is 54 years old, older than the Iowa average of 45.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 776 vehicles a day, roughly 18% of them trucks, projected to reach 776 by 2043. The structure is 68 ft (20.7 m) long and 30 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesFM
CrossesDd
Location089210201
RouteCounty Highway 0
CountyHardin County
StateIowa
Coordinates42.55726, -93.28999
Functional classRural Major Collector

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck4 PoorAdvanced section loss, deterioration, spalling or scour.
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 inspectionFebruary 2023
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 geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating62.9 US tons
Inventory rating27.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 20
Structure length68 ft (20.7 m)
Longest span66 ft (20.1 m)
Deck width30 ft (9.1 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic776 (2022)
Projected traffic776 by 2043
Trucks18%
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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was FM over Dd built?

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

What condition is FM over Dd in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in February 2023.

How much traffic does FM over Dd carry?

About 776 vehicles per day (2022 count), of which roughly 18% are trucks.

How long is FM over Dd?

The structure is 68 ft (20.7 m) long with a longest span of 66 ft (20.1 m) and a deck 30 ft wide.

Who owns FM over Dd?

It is owned by the County Highway Agency.