US Bridges

FM over Black Hawk

Fair

Grundy County, Iowa · 088173503 · Structure no. 000000000165221

Built
1981
44 years old
Condition
Fair
inspected April 2024
Type
Slab
Concrete Continuous
Length
103 ft
3 main spans
Daily traffic
79
2022 count
Owner
County
County Highway Agency

About this bridge

FM over Black Hawk is a concrete continuous slab carrying FM over Black Hawk in Grundy County, Iowa. It was built in 1981, so it is 44 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 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 79 vehicles a day, projected to reach 79 by 2044. The structure is 103 ft (31.4 m) long and 33 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesFM
CrossesBlack Hawk
Location088173503
RouteCounty Highway 0
CountyGrundy County
StateIowa
Coordinates42.3954, -92.8034
Functional classRural Minor 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2024
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 geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating55 US tons
Inventory rating34 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 20
Structure length103 ft (31.4 m)
Longest span39 ft (11.9 m)
Deck width33 ft (10.2 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic79 (2022)
Projected traffic79 by 2044
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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 proposedOther structural work, including hydraulic replacements
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was FM over Black Hawk built?

It was built in 1981, making it 44 years old in 2025.

What condition is FM over Black Hawk 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 2024.

How much traffic does FM over Black Hawk carry?

About 79 vehicles per day (2022 count).

How long is FM over Black Hawk?

The structure is 103 ft (31.4 m) long with a longest span of 39 ft (11.9 m) and a deck 33 ft wide.

Who owns FM over Black Hawk?

It is owned by the County Highway Agency.