US Bridges

170th Ave. over Small Stream

Good

Clinton County, Iowa · 083E23202 · Structure no. 000000000124881

Built
1992
33 years old
Condition
Good
inspected January 2024
Type
Tee Beam
Prestressed Concrete
Length
30 ft
1 main span
Daily traffic
35
2022 count
Owner
County
County Highway Agency

About this bridge

170th Ave. over Small Stream is a prestressed concrete tee beam carrying 170th Ave. over Small Stream in Clinton County, Iowa. It was built in 1992, so it is 33 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 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 35 vehicles a day, projected to reach 35 by 2044. The structure is 30 ft (9.1 m) long and 24 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
Carries170th Ave.
CrossesSmall Stream
Location083E23202
RouteCounty Highway 0
CountyClinton County
StateIowa
Coordinates41.95275, -90.76192
Functional classRural Local

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.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 2024
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating65.1 US tons
Inventory rating39 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans1
Design loadHS 20
Structure length30 ft (9.1 m)
Longest span29 ft (8.8 m)
Deck width24 ft (7.3 m)
Roadway width24 ft (7.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic35 (2022)
Projected traffic35 by 2044
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was 170th Ave. over Small Stream built?

It was built in 1992, making it 33 years old in 2025.

What condition is 170th Ave. over Small Stream 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 January 2024.

How much traffic does 170th Ave. over Small Stream carry?

About 35 vehicles per day (2022 count).

How long is 170th Ave. over Small Stream?

The structure is 30 ft (9.1 m) long with a longest span of 29 ft (8.8 m) and a deck 24 ft wide.

Who owns 170th Ave. over Small Stream?

It is owned by the County Highway Agency.