US Bridges

NW 16th ST over Four Mile Creek

Fair

Polk County, Iowa · 081241502 · Structure no. 000000000282951

Built
1970
55 years old
Condition
Fair
inspected May 2023
Type
Stringer/Multi-beam or Girder
Concrete
Length
25 ft
1 main span
Daily traffic
50
2021 count
Owner
County
County Highway Agency

About this bridge

NW 16th ST over Four Mile Creek is a concrete stringer/multi-beam or girder carrying NW 16th ST over Four Mile Creek in Polk County, Iowa. It was built in 1970, so it is 55 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 50 vehicles a day, projected to reach 50 by 2043. The structure is 25 ft (7.6 m) long and 31 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesNW 16th ST
CrossesFour Mile Creek
Location081241502
RouteCounty Highway 0
CountyPolk County
StateIowa
Coordinates41.83041, -93.63897
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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating50.2 US tons
Inventory rating30.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 20
Structure length25 ft (7.6 m)
Longest span24 ft (7.3 m)
Deck width31 ft (9.5 m)
Roadway width30 ft (9.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic50 (2021)
Projected traffic50 by 2043
Trucks0%
Lanes on structure2
Traffic directionTwo-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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was NW 16th ST over Four Mile Creek built?

It was built in 1970, making it 55 years old in 2025.

What condition is NW 16th ST over Four Mile 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 May 2023.

How much traffic does NW 16th ST over Four Mile Creek carry?

About 50 vehicles per day (2021 count).

How long is NW 16th ST over Four Mile Creek?

The structure is 25 ft (7.6 m) long with a longest span of 24 ft (7.3 m) and a deck 31 ft wide.

Who owns NW 16th ST over Four Mile Creek?

It is owned by the County Highway Agency.