US Bridges

280th ST over Boone River

Good

Hamilton County, Iowa · 087250601 · Structure no. 000000000366325

Built
2019
6 years old
Condition
Good
inspected September 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
457 ft
3 main spans
Daily traffic
80
2022 count
Owner
County
County Highway Agency

About this bridge

280th ST over Boone River is a prestressed concrete stringer/multi-beam or girder carrying 280th ST over Boone River in Hamilton County, Iowa. It was built in 2019, so it is 6 years old, younger than the Iowa average of 45.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 80 vehicles a day, projected to reach 80 by 2043. The structure is 457 ft (139.3 m) long and 35 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
Carries280th ST
CrossesBoone River
Location087250601
RouteCounty Highway 0
CountyHamilton County
StateIowa
Coordinates42.38369, -93.80837
Functional classRural Minor Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation8: Equal to present desirable criteria
Deck geometry8: Equal to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating46.4 US tons
Inventory rating35.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHL 93
Structure length457 ft (139.3 m)
Longest span152 ft (46.3 m)
Deck width35 ft (10.6 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic80 (2022)
Projected traffic80 by 2043
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 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$30,000 (2023 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was 280th ST over Boone River built?

It was built in 2019, making it 6 years old in 2025.

What condition is 280th ST over Boone River in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in September 2023.

How much traffic does 280th ST over Boone River carry?

About 80 vehicles per day (2022 count).

How long is 280th ST over Boone River?

The structure is 457 ft (139.3 m) long with a longest span of 152 ft (46.3 m) and a deck 35 ft wide.

Who owns 280th ST over Boone River?

It is owned by the County Highway Agency.