US Bridges

170th Ave. over Drainage Ditch 12

Good

Clinton County, Iowa · 082E20802 · Structure no. 000000000123150

Built
1962
63 years old
Condition
Good
inspected January 2024
Type
Slab
Concrete Continuous
Length
77 ft
3 main spans
Daily traffic
35
2022 count
Owner
County
County Highway Agency

About this bridge

170th Ave. over Drainage Ditch 12 is a concrete continuous slab carrying 170th Ave. over Drainage Ditch 12 in Clinton County, Iowa. It was built in 1962, so it is 63 years old, older 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 77 ft (23.5 m) long and 26 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
Carries170th Ave.
CrossesDrainage Ditch 12
Location082E20802
RouteCounty Highway 0
CountyClinton County
StateIowa
Coordinates41.92081, -90.76189
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
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 evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating50.9 US tons
Inventory rating29.3 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 15
Structure length77 ft (23.5 m)
Longest span29 ft (8.8 m)
Deck width26 ft (8 m)
Roadway width24 ft (7.3 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 Drainage Ditch 12 built?

It was built in 1962, making it 63 years old in 2025.

What condition is 170th Ave. over Drainage Ditch 12 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 Drainage Ditch 12 carry?

About 35 vehicles per day (2022 count).

How long is 170th Ave. over Drainage Ditch 12?

The structure is 77 ft (23.5 m) long with a longest span of 29 ft (8.8 m) and a deck 26 ft wide.

Who owns 170th Ave. over Drainage Ditch 12?

It is owned by the County Highway Agency.