US Bridges

Ansborough Ave over Black Hawk Creek

Fair

Black Hawk County, Iowa · City Bridge No. 17 · Structure no. 000000000012050

Built
1971
54 years old, rebuilt 1988
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
487 ft
6 main spans
Daily traffic
8,392
2022 count
Owner
City
City or Municipal Highway Agency

About this bridge

Ansborough Ave over Black Hawk Creek is a prestressed concrete continuous stringer/multi-beam or girder carrying Ansborough Ave over Black Hawk Creek in Black Hawk County, Iowa. It was built in 1971 and reconstructed in 1988, so it is 54 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 8,392 vehicles a day, projected to reach 8,392 by 2043. The structure is 487 ft (148.4 m) long and 91 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesAnsborough Ave
CrossesBlack Hawk Creek
LocationCity Bridge No. 17
RouteCity Street 0
CountyBlack Hawk County
StateIowa
Coordinates42.48778, -92.37698
Functional classUrban 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 protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating48.6 US tons
Inventory rating28.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans6
Design loadHS 20
Structure length487 ft (148.4 m)
Longest span82 ft (25 m)
Deck width91 ft (27.7 m)
Roadway width56 ft (17.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic8,392 (2022)
Projected traffic8,392 by 2043
Trucks0%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedWidening of existing bridge without deck rehabilitation
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Ansborough Ave over Black Hawk Creek built?

It was built in 1971, making it 54 years old in 2025. It was reconstructed in 1988.

What condition is Ansborough Ave over Black Hawk Creek 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 Ansborough Ave over Black Hawk Creek carry?

About 8,392 vehicles per day (2022 count).

How long is Ansborough Ave over Black Hawk Creek?

The structure is 487 ft (148.4 m) long with a longest span of 82 ft (25 m) and a deck 91 ft wide.

Who owns Ansborough Ave over Black Hawk Creek?

It is owned by the City or Municipal Highway Agency.