US Bridges

FM over Skunk River

Fair

Marion County, Iowa · 077180304 · Structure no. 000000000240825

Built
1948
77 years old, rebuilt 1996
Condition
Fair
inspected December 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
337 ft
4 main spans
Daily traffic
1,300
2022 count
Owner
County
County Highway Agency

About this bridge

FM over Skunk River is a steel continuous stringer/multi-beam or girder carrying FM over Skunk River in Marion County, Iowa. It was built in 1948 and reconstructed in 1996, 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.

It carries about 1,300 vehicles a day, roughly 7% of them trucks, projected to reach 1,300 by 2044. The structure is 337 ft (102.7 m) long and 33 ft wide. If it were closed, the detour would be 8.7 mi (14 km).

Location

Open in Google Maps
CarriesFM
CrossesSkunk River
Location077180304
RouteCounty Highway 0
CountyMarion County
StateIowa
Coordinates41.4967, -92.921
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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
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 geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating63.9 US tons
Inventory rating38.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length337 ft (102.7 m)
Longest span94 ft (28.7 m)
Deck width33 ft (10 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,300 (2022)
Projected traffic1,300 by 2044
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.7 mi (14 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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was FM over Skunk River built?

It was built in 1948, making it 77 years old in 2025. It was reconstructed in 1996.

What condition is FM over Skunk River 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 over Skunk River carry?

About 1,300 vehicles per day (2022 count), of which roughly 7% are trucks.

How long is FM over Skunk River?

The structure is 337 ft (102.7 m) long with a longest span of 94 ft (28.7 m) and a deck 33 ft wide.

Who owns FM over Skunk River?

It is owned by the County Highway Agency.