US Bridges

FM over Nishnabotna River

Fair

Montgomery County, Iowa · 071393603 · Structure no. 000000000255041

Built
1972
53 years old, rebuilt 2019
Condition
Fair
inspected May 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
316 ft
4 main spans
Daily traffic
133
2021 count
Owner
County
County Highway Agency

About this bridge

FM over Nishnabotna River is a steel continuous stringer/multi-beam or girder carrying FM over Nishnabotna River in Montgomery County, Iowa. It was built in 1972 and reconstructed in 2019, so it is 53 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 133 vehicles a day, roughly 14% of them trucks, projected to reach 133 by 2043. The structure is 316 ft (96.3 m) long and 32 ft wide. If it were closed, the detour would be 8.7 mi (14 km).

Location

Open in Google Maps
CarriesFM
CrossesNishnabotna River
Location071393603
RouteCounty Highway 0
CountyMontgomery County
StateIowa
Coordinates40.91579, -95.27608
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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating48.3 US tons
Inventory rating31 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadH 20
Structure length316 ft (96.3 m)
Longest span89 ft (27.1 m)
Deck width32 ft (9.8 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic133 (2021)
Projected traffic133 by 2043
Trucks14%
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$3.4 million (2024 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was FM over Nishnabotna River built?

It was built in 1972, making it 53 years old in 2025. It was reconstructed in 2019.

What condition is FM over Nishnabotna 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 May 2023.

How much traffic does FM over Nishnabotna River carry?

About 133 vehicles per day (2021 count), of which roughly 14% are trucks.

How long is FM over Nishnabotna River?

The structure is 316 ft (96.3 m) long with a longest span of 89 ft (27.1 m) and a deck 32 ft wide.

Who owns FM over Nishnabotna River?

It is owned by the County Highway Agency.