US Bridges

780 170th ST over Br Boone River #8

Fair

Hancock County, Iowa · 095253101 · Structure no. 000000000173481

Built
1978
47 years old
Condition
Fair
inspected March 2024
Type
Slab
Concrete Continuous
Length
67 ft
3 main spans
Daily traffic
15
2022 count
Owner
County
County Highway Agency

About this bridge

780 170th ST over Br Boone River #8 is a concrete continuous slab carrying 780 170th ST over Br Boone River #8 in Hancock County, Iowa. It was built in 1978, so it is 47 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 15 vehicles a day, projected to reach 15 by 2044. The structure is 67 ft (20.4 m) long and 26 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
Carries780 170th ST
CrossesBr Boone River #8
Location095253101
RouteCounty Highway 0
CountyHancock County
StateIowa
Coordinates43.00958, -93.83633
Functional classRural Local

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.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMarch 2024
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 adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating46 US tons
Inventory rating27.6 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 15
Structure length67 ft (20.4 m)
Longest span26 ft (7.9 m)
Deck width26 ft (7.9 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic15 (2022)
Projected traffic15 by 2044
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$17,000 (2024 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was 780 170th ST over Br Boone River #8 built?

It was built in 1978, making it 47 years old in 2025.

What condition is 780 170th ST over Br Boone River #8 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 March 2024.

How much traffic does 780 170th ST over Br Boone River #8 carry?

About 15 vehicles per day (2022 count).

How long is 780 170th ST over Br Boone River #8?

The structure is 67 ft (20.4 m) long with a longest span of 26 ft (7.9 m) and a deck 26 ft wide.

Who owns 780 170th ST over Br Boone River #8?

It is owned by the County Highway Agency.