US Bridges

Local 470th ST over Mill Creek

Fair

Cherokee County, Iowa · 093403201 · Structure no. 000000000109661

Built
1974
51 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
208 ft
3 main spans
Daily traffic
71
2022 count
Owner
County
County Highway Agency

About this bridge

Local 470th ST over Mill Creek is a prestressed concrete stringer/multi-beam or girder carrying Local 470th ST over Mill Creek in Cherokee County, Iowa. It was built in 1974, so it is 51 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 71 vehicles a day, projected to reach 71 by 2043. The structure is 208 ft (63.4 m) long and 26 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesLocal 470th ST
CrossesMill Creek
Location093403201
RouteCounty Highway 0
CountyCherokee County
StateIowa
Coordinates42.83739, -95.60007
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2023
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 geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating47 US tons
Inventory rating19.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length208 ft (63.4 m)
Longest span69 ft (21 m)
Deck width26 ft (7.9 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic71 (2022)
Projected traffic71 by 2043
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 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 proposedOther structural work, including hydraulic replacements
Estimated improvement cost$30,000 (2023 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Local 470th ST over Mill Creek built?

It was built in 1974, making it 51 years old in 2025.

What condition is Local 470th ST over Mill 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 August 2023.

How much traffic does Local 470th ST over Mill Creek carry?

About 71 vehicles per day (2022 count).

How long is Local 470th ST over Mill Creek?

The structure is 208 ft (63.4 m) long with a longest span of 69 ft (21 m) and a deck 26 ft wide.

Who owns Local 470th ST over Mill Creek?

It is owned by the County Highway Agency.