US Bridges

Ia 21 over Stream

Fair

Black Hawk County, Iowa · 4.6 Mi. S of Jct. US 20 · Structure no. 000000000014980

Built
1959
66 years old
Condition
Fair
inspected April 2023
Type
Culvert
Concrete Continuous
Length
21 ft
2 main spans
Daily traffic
2,480
2022 count
Owner
State
State Highway Agency

About this bridge

Ia 21 over Stream is a concrete continuous culvert carrying Ia 21 over Stream in Black Hawk 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 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 2,480 vehicles a day, roughly 11% of them trucks, projected to reach 2,480 by 2042. The structure is 21 ft (6.4 m) long. If it were closed, the detour would be 5 mi (8 km).

Location

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CarriesIa 21
CrossesStream
Location4.6 Mi. S of Jct. US 20
RouteState Highway 21
CountyBlack Hawk County
StateIowa
Coordinates42.38644, -92.34714
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
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 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
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating27 US tons
Inventory rating20 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadH 20
Structure length21 ft (6.4 m)
Longest span10 ft (3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,480 (2022)
Projected traffic2,480 by 2042
Trucks11%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 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 Stream built?

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

What condition is Ia 21 over Stream 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 April 2023.

How much traffic does Ia 21 over Stream carry?

About 2,480 vehicles per day (2022 count), of which roughly 11% are trucks.

How long is Ia 21 over Stream?

The structure is 21 ft (6.4 m) long with a longest span of 10 ft (3 m).

Who owns Ia 21 over Stream?

It is owned by the State Highway Agency.