US Bridges

Ia 21 over Iowa River

Fair

Iowa County, Iowa · 1.1 Mi. N of Jct. Ia #212 · Structure no. 000000000029401

Built
1982
43 years old
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
628 ft
7 main spans
Daily traffic
2,370
2022 count
Owner
State
State Highway Agency

About this bridge

Ia 21 over Iowa River is a prestressed concrete stringer/multi-beam or girder carrying Ia 21 over Iowa River in Iowa County, Iowa. It was built in 1982, so it is 43 years old, younger 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 6 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 2,370 vehicles a day, roughly 8% of them trucks, projected to reach 2,370 by 2042. The structure is 628 ft (191.4 m) long and 47 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

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CarriesIa 21
CrossesIowa River
Location1.1 Mi. N of Jct. Ia #212
RouteState Highway 21
CountyIowa County
StateIowa
Coordinates41.85868, -92.27802
Functional classRural Minor Arterial

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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2023
Inspection intervalevery 22 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating99.8 US tons
Inventory rating48.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans7
Design loadHS 20
Structure length628 ft (191.4 m)
Longest span97 ft (29.6 m)
Deck width47 ft (14.4 m)
Roadway width44 ft (13.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,370 (2022)
Projected traffic2,370 by 2042
Trucks8%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 km)
TollOn a free road
National Highway SystemNo

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 Ia 21 over Iowa River built?

It was built in 1982, making it 43 years old in 2025.

What condition is Ia 21 over Iowa 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 September 2023.

How much traffic does Ia 21 over Iowa River carry?

About 2,370 vehicles per day (2022 count), of which roughly 8% are trucks.

How long is Ia 21 over Iowa River?

The structure is 628 ft (191.4 m) long with a longest span of 97 ft (29.6 m) and a deck 47 ft wide.

Who owns Ia 21 over Iowa River?

It is owned by the State Highway Agency.