US Bridges

Ia 175 over Boyer River

Fair

Sac County, Iowa · 0.7 Mi. S of N JCT Ia 471 · Structure no. 000000000046660

Built
1967
58 years old
Condition
Fair
inspected October 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
170 ft
3 main spans
Daily traffic
1,820
2022 count
Owner
State
State Highway Agency

About this bridge

Ia 175 over Boyer River is a prestressed concrete stringer/multi-beam or girder carrying Ia 175 over Boyer River in Sac County, Iowa. It was built in 1967, so it is 58 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 1,820 vehicles a day, roughly 31% of them trucks, projected to reach 1,820 by 2042. The structure is 170 ft (51.8 m) long and 35 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesIa 175
CrossesBoyer River
Location0.7 Mi. S of N JCT Ia 471
RouteState Highway 175
CountySac County
StateIowa
Coordinates42.31159, -95.13093
Functional classRural Minor Arterial

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.
Superstructure8 Very GoodNo problems noted.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating72.8 US tons
Inventory rating28.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length170 ft (51.8 m)
Longest span57 ft (17.4 m)
Deck width35 ft (10.8 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,820 (2022)
Projected traffic1,820 by 2042
Trucks31%
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

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Ia 175 over Boyer River built?

It was built in 1967, making it 58 years old in 2025.

What condition is Ia 175 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 October 2023.

How much traffic does Ia 175 over Boyer River carry?

About 1,820 vehicles per day (2022 count), of which roughly 31% are trucks.

How long is Ia 175 over Boyer River?

The structure is 170 ft (51.8 m) long with a longest span of 57 ft (17.4 m) and a deck 35 ft wide.

Who owns Ia 175 over Boyer River?

It is owned by the State Highway Agency.