US Bridges

170th St. over Drainage

Fair

Clinton County, Iowa · 082E10901 · Structure no. 000000000122871

Built
1987
38 years old
Condition
Fair
inspected January 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
26 ft
1 main span
Daily traffic
21
2022 count
Owner
County
County Highway Agency

About this bridge

170th St. over Drainage is a steel stringer/multi-beam or girder carrying 170th St. over Drainage in Clinton County, Iowa. It was built in 1987, so it is 38 years old, younger 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 5 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 21 vehicles a day, projected to reach 21 by 2044. The structure is 26 ft (7.9 m) long and 20 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
Carries170th St.
CrossesDrainage
Location082E10901
RouteCounty Highway 0
CountyClinton County
StateIowa
Coordinates41.93147, -90.85458
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating48.2 US tons
Inventory rating36.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckWood or timber
Main spans1
Design loadH 20
Structure length26 ft (7.9 m)
Longest span24 ft (7.3 m)
Deck width20 ft (6.1 m)
Roadway width18 ft (5.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic21 (2022)
Projected traffic21 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 St. over Drainage built?

It was built in 1987, making it 38 years old in 2025.

What condition is 170th St. over Drainage 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 170th St. over Drainage carry?

About 21 vehicles per day (2022 count).

How long is 170th St. over Drainage?

The structure is 26 ft (7.9 m) long with a longest span of 24 ft (7.3 m) and a deck 20 ft wide.

Who owns 170th St. over Drainage?

It is owned by the County Highway Agency.