US Bridges

FM over Inlet Blackhawk Lk

Fair

Sac County, Iowa · 086360903 · Structure no. 000000000299011

Built
1989
36 years old
Condition
Fair
inspected August 2024
Type
Slab
Concrete Continuous
Length
78 ft
3 main spans
Daily traffic
330
2022 count
Owner
County
County Highway Agency

About this bridge

FM over Inlet Blackhawk Lk is a concrete continuous slab carrying FM over Inlet Blackhawk Lk in Sac County, Iowa. It was built in 1989, so it is 36 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 330 vehicles a day, roughly 10% of them trucks, projected to reach 330 by 2044. The structure is 78 ft (23.8 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
CrossesInlet Blackhawk Lk
Location086360903
RouteCounty Highway 0
CountySac County
StateIowa
Coordinates42.28249, -95.0481
Functional classRural Major 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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionAugust 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 geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating68.6 US tons
Inventory rating40.9 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length78 ft (23.8 m)
Longest span29 ft (8.8 m)
Deck width33 ft (10.1 m)
Roadway width31 ft (9.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic330 (2022)
Projected traffic330 by 2044
Trucks10%
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 Inlet Blackhawk Lk built?

It was built in 1989, making it 36 years old in 2025.

What condition is FM over Inlet Blackhawk Lk 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 August 2024.

How much traffic does FM over Inlet Blackhawk Lk carry?

About 330 vehicles per day (2022 count), of which roughly 10% are trucks.

How long is FM over Inlet Blackhawk Lk?

The structure is 78 ft (23.8 m) long with a longest span of 29 ft (8.8 m) and a deck 33 ft wide.

Who owns FM over Inlet Blackhawk Lk?

It is owned by the County Highway Agency.