US Bridges

FM 570 120th ST over Boone River

Fair

Hancock County, Iowa · 094262601 · Structure no. 000000000172991

Built
1979
46 years old
Condition
Fair
inspected April 2023
Type
Slab
Concrete Continuous
Length
116 ft
3 main spans
Daily traffic
439
2022 count
Owner
County
County Highway Agency

About this bridge

FM 570 120th ST over Boone River is a concrete continuous slab carrying FM 570 120th ST over Boone River in Hancock County, Iowa. It was built in 1979, so it is 46 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 439 vehicles a day, roughly 20% of them trucks, projected to reach 439 by 2043. The structure is 116 ft (35.4 m) long and 32 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
CarriesFM 570 120th ST
CrossesBoone River
Location094262601
RouteCounty Highway 0
CountyHancock County
StateIowa
Coordinates42.9372, -93.87734
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating54 US tons
Inventory rating31.5 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 20
Structure length116 ft (35.4 m)
Longest span44 ft (13.4 m)
Deck width32 ft (9.8 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic439 (2022)
Projected traffic439 by 2043
Trucks20%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.1 mi (13 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 570 120th ST over Boone River built?

It was built in 1979, making it 46 years old in 2025.

What condition is FM 570 120th ST over Boone 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 April 2023.

How much traffic does FM 570 120th ST over Boone River carry?

About 439 vehicles per day (2022 count), of which roughly 20% are trucks.

How long is FM 570 120th ST over Boone River?

The structure is 116 ft (35.4 m) long with a longest span of 44 ft (13.4 m) and a deck 32 ft wide.

Who owns FM 570 120th ST over Boone River?

It is owned by the County Highway Agency.