US Bridges

FM over Drainage

Fair

Mahaska County, Iowa · 077140101 · Structure no. 000000000237701

Built
1990
35 years old
Condition
Fair
inspected December 2023
Type
Tee Beam
Prestressed Concrete
Length
41 ft
1 main span
Daily traffic
60
2022 count
Owner
County
County Highway Agency

About this bridge

FM over Drainage is a prestressed concrete tee beam carrying FM over Drainage in Mahaska County, Iowa. It was built in 1990, so it is 35 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 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 60 vehicles a day, projected to reach 60 by 2043. The structure is 41 ft (12.5 m) long and 28 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesFM
CrossesDrainage
Location077140101
RouteCounty Highway 0
CountyMahaska County
StateIowa
Coordinates41.50949, -92.42426
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
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 protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionDecember 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 geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating67.8 US tons
Inventory rating40.6 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length41 ft (12.5 m)
Longest span41 ft (12.5 m)
Deck width28 ft (8.5 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic60 (2022)
Projected traffic60 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 FM over Drainage built?

It was built in 1990, making it 35 years old in 2025.

What condition is FM over Drainage 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 2023.

How much traffic does FM over Drainage carry?

About 60 vehicles per day (2022 count).

How long is FM over Drainage?

The structure is 41 ft (12.5 m) long with a longest span of 41 ft (12.5 m) and a deck 28 ft wide.

Who owns FM over Drainage?

It is owned by the County Highway Agency.