US Bridges

US 71 over East Nishnabotna River

Fair

Audubon County, Iowa · 1.1 Mi. S of Jct. Ia 44 · Structure no. 000000000014120

Built
1959
66 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
246 ft
3 main spans
Daily traffic
2,470
2022 count
Owner
State
State Highway Agency

About this bridge

US 71 over East Nishnabotna River is a steel continuous stringer/multi-beam or girder carrying US 71 over East Nishnabotna River in Audubon County, Iowa. It was built in 1959, so it is 66 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 2,470 vehicles a day, roughly 20% of them trucks, projected to reach 2,470 by 2042. The structure is 246 ft (75 m) long and 35 ft wide. If it were closed, the detour would be 19.9 mi (32 km).

Location

Open in Google Maps
CarriesUS 71
CrossesEast Nishnabotna River
Location1.1 Mi. S of Jct. Ia 44
RouteU.S. Route 71
CountyAudubon County
StateIowa
Coordinates41.65175, -94.8992
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 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 geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating53.6 US tons
Inventory rating32.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length246 ft (75 m)
Longest span94 ft (28.7 m)
Deck width35 ft (10.6 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,470 (2022)
Projected traffic2,470 by 2042
Trucks20%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed19.9 mi (32 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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 US 71 over East Nishnabotna River built?

It was built in 1959, making it 66 years old in 2025.

What condition is US 71 over East 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 June 2023.

How much traffic does US 71 over East Nishnabotna River carry?

About 2,470 vehicles per day (2022 count), of which roughly 20% are trucks.

How long is US 71 over East Nishnabotna River?

The structure is 246 ft (75 m) long with a longest span of 94 ft (28.7 m) and a deck 35 ft wide.

Who owns US 71 over East Nishnabotna River?

It is owned by the State Highway Agency.