US Bridges

318th ST over Cox Creek

PoorPosted for load

Clayton County, Iowa · 092052004 · Structure no. 000000000118990

Built
1920
105 years old
Condition
Poor
inspected October 2024
Type
Slab
Concrete
Length
21 ft
1 main span
Daily traffic
30
2022 count
Owner
County
County Highway Agency

About this bridge

318th ST over Cox Creek is a concrete slab carrying 318th ST over Cox Creek in Clayton County, Iowa. It was built in 1920, so it is 105 years old, older than the Iowa average of 45.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. Its operating status is: posted for other load-capacity restriction.

It carries about 30 vehicles a day, projected to reach 30 by 2044. The structure is 21 ft (6.4 m) long and 18 ft wide.

Location

Open in Google Maps
Carries318th ST
CrossesCox Creek
Location092052004
RouteCounty Highway 0
CountyClayton County
StateIowa
Coordinates42.76452, -91.46266
Functional classRural Local

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusPosted for other load-capacity restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry8: Equal to present desirable criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating55.3 US tons
Inventory rating33.8 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length21 ft (6.4 m)
Longest span20 ft (6.1 m)
Deck width18 ft (5.5 m)
Roadway width16 ft (4.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic30 (2022)
Projected traffic30 by 2044
Trucks0%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed—
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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was 318th ST over Cox Creek built?

It was built in 1920, making it 105 years old in 2025.

What condition is 318th ST over Cox Creek in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in October 2024.

How much traffic does 318th ST over Cox Creek carry?

About 30 vehicles per day (2022 count).

How long is 318th ST over Cox Creek?

The structure is 21 ft (6.4 m) long with a longest span of 20 ft (6.1 m) and a deck 18 ft wide.

Who owns 318th ST over Cox Creek?

It is owned by the County Highway Agency.