US Bridges

FM over Big Sioux River

Fair

Plymouth County, Iowa · 90948 · Structure no. 000000000272011

Built
1967
58 years old
Condition
Fair
inspected June 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
447 ft
5 main spans
Daily traffic
589
2022 count
Owner
County
County Highway Agency

About this bridge

FM over Big Sioux River is a steel continuous stringer/multi-beam or girder carrying FM over Big Sioux River in Plymouth County, Iowa. It was built in 1967, so it is 58 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 589 vehicles a day, roughly 16% of them trucks, projected to reach 589 by 2044. The structure is 447 ft (136.2 m) long and 30 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
CarriesFM
CrossesBig Sioux River
Location90948
RouteCounty Highway 0
CountyPlymouth County
StateIowa
Coordinates42.62638, -96.51449
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.
Superstructure7 GoodSome minor problems.
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 inspectionJune 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 alignment8: Equal to present desirable criteria
Operating rating53.9 US tons
Inventory rating32.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans5
Design loadH 20
Structure length447 ft (136.2 m)
Longest span98 ft (29.9 m)
Deck width30 ft (9.1 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic589 (2022)
Projected traffic589 by 2044
Trucks16%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.1 mi (13 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 Big Sioux River built?

It was built in 1967, making it 58 years old in 2025.

What condition is FM over Big Sioux 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 June 2024.

How much traffic does FM over Big Sioux River carry?

About 589 vehicles per day (2022 count), of which roughly 16% are trucks.

How long is FM over Big Sioux River?

The structure is 447 ft (136.2 m) long with a longest span of 98 ft (29.9 m) and a deck 30 ft wide.

Who owns FM over Big Sioux River?

It is owned by the County Highway Agency.