US Bridges

170th ST over Little Minerva Creek

FairPosted for load

Story County, Iowa · 084211101 · Structure no. 000000000315000

Built
1958
67 years old, rebuilt 1974
Condition
Fair
inspected December 2022
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
25 ft
1 main span
Daily traffic
11
2022 count
Owner
County
County Highway Agency

About this bridge

170th ST over Little Minerva Creek is a wood or timber stringer/multi-beam or girder carrying 170th ST over Little Minerva Creek in Story County, Iowa. It was built in 1958 and reconstructed in 1974, so it is 67 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. Its operating status is: posted for load restriction.

It carries about 11 vehicles a day, projected to reach 11 by 2043. The structure is 25 ft (7.6 m) long and 22 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
Carries170th ST
CrossesLittle Minerva Creek
Location084211101
RouteCounty Highway 0
CountyStory County
StateIowa
Coordinates42.10685, -93.26126
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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionDecember 2022
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating23 US tons
Inventory rating15 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans1
Design loadUnknown
Structure length25 ft (7.6 m)
Longest span22 ft (6.7 m)
Deck width22 ft (6.7 m)
Roadway width22 ft (6.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11 (2022)
Projected traffic11 by 2043
Trucks0%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 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 170th ST over Little Minerva Creek built?

It was built in 1958, making it 67 years old in 2025. It was reconstructed in 1974.

What condition is 170th ST over Little Minerva Creek 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 December 2022.

How much traffic does 170th ST over Little Minerva Creek carry?

About 11 vehicles per day (2022 count).

How long is 170th ST over Little Minerva Creek?

The structure is 25 ft (7.6 m) long with a longest span of 22 ft (6.7 m) and a deck 22 ft wide.

Who owns 170th ST over Little Minerva Creek?

It is owned by the County Highway Agency.