US Bridges

FM over Drainage

PoorPosted for load

Mahaska County, Iowa · 077153203 · Structure no. 000000000238180

Built
1954
71 years old
Condition
Poor
inspected January 2025
Type
Channel Beam
Concrete
Length
25 ft
1 main span
Daily traffic
30
2022 count
Owner
County
County Highway Agency

About this bridge

FM over Drainage is a concrete channel beam carrying FM over Drainage in Mahaska County, Iowa. It was built in 1954, so it is 71 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 3 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. Its operating status is: posted for load restriction.

It carries about 30 vehicles a day, projected to reach 30 by 2045. The structure is 25 ft (7.6 m) long and 23 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesFM
CrossesDrainage
Location077153203
RouteCounty Highway 0
CountyMahaska County
StateIowa
Coordinates41.43714, -92.61336
Functional classRural Minor 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.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure3 SeriousLoss of section, deterioration, spalling or scour have seriously affected primary structural components.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 2025
Inspection intervalevery 12 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating4 US tons
Inventory rating0 US tons

Structure

Structure typeChannel Beam
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length25 ft (7.6 m)
Longest span23 ft (7 m)
Deck width23 ft (6.9 m)
Roadway width21 ft (6.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic30 (2022)
Projected traffic30 by 2045
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 1954, making it 71 years old in 2025.

What condition is FM over Drainage 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 January 2025.

How much traffic does FM over Drainage carry?

About 30 vehicles per day (2022 count).

How long is FM over Drainage?

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

Who owns FM over Drainage?

It is owned by the County Highway Agency.