US Bridges

296th ST over Boyer River

Fair

Harrison County, Iowa · 078441203 · Structure no. 000000000177701

Built
1974
51 years old
Condition
Fair
inspected January 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
253 ft
3 main spans
Daily traffic
577
2022 count
Owner
County
County Highway Agency

About this bridge

296th ST over Boyer River is a steel continuous stringer/multi-beam or girder carrying 296th ST over Boyer River in Harrison County, Iowa. It was built in 1974, so it is 51 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 577 vehicles a day, roughly 16% of them trucks, projected to reach 577 by 2044. The structure is 253 ft (77.1 m) long and 32 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
Carries296th ST
CrossesBoyer River
Location078441203
RouteCounty Highway 0
CountyHarrison County
StateIowa
Coordinates41.57349, -95.84557
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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 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 alignment8: Equal to present desirable criteria
Operating rating52.7 US tons
Inventory rating33.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length253 ft (77.1 m)
Longest span98 ft (29.9 m)
Deck width32 ft (9.8 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic577 (2022)
Projected traffic577 by 2044
Trucks16%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 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—
NavigationNo navigation control on waterway

Frequently asked questions

When was 296th ST over Boyer River built?

It was built in 1974, making it 51 years old in 2025.

What condition is 296th ST over Boyer 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 January 2024.

How much traffic does 296th ST over Boyer River carry?

About 577 vehicles per day (2022 count), of which roughly 16% are trucks.

How long is 296th ST over Boyer River?

The structure is 253 ft (77.1 m) long with a longest span of 98 ft (29.9 m) and a deck 32 ft wide.

Who owns 296th ST over Boyer River?

It is owned by the County Highway Agency.