US Bridges

300th ST over Miners Creek

PoorPosted for load

Clayton County, Iowa · 092031205 · Structure no. 000000000118670

Built
1916
109 years old
Condition
Poor
inspected October 2023
Type
Slab
Concrete
Length
40 ft
1 main span
Daily traffic
39
2022 count
Owner
County
County Highway Agency

About this bridge

300th ST over Miners Creek is a concrete slab carrying 300th ST over Miners Creek in Clayton County, Iowa. It was built in 1916, so it is 109 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 3 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 load restriction.

It carries about 39 vehicles a day, projected to reach 39 by 2043. The structure is 40 ft (12.2 m) long and 21 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
Carries300th ST
CrossesMiners Creek
Location092031205
RouteCounty Highway 0
CountyClayton County
StateIowa
Coordinates42.79686, -91.13711
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
Deck4 PoorAdvanced section loss, deterioration, spalling or scour.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure3 SeriousLoss of section, deterioration, spalling or scour have seriously affected primary structural components.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionOctober 2023
Inspection intervalevery 12 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment6: Equal to present minimum criteria
Operating rating11 US tons
Inventory rating11 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length40 ft (12.2 m)
Longest span38 ft (11.6 m)
Deck width21 ft (6.3 m)
Roadway width16 ft (5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic39 (2022)
Projected traffic39 by 2043
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was 300th ST over Miners Creek built?

It was built in 1916, making it 109 years old in 2025.

What condition is 300th ST over Miners 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 2023.

How much traffic does 300th ST over Miners Creek carry?

About 39 vehicles per day (2022 count).

How long is 300th ST over Miners Creek?

The structure is 40 ft (12.2 m) long with a longest span of 38 ft (11.6 m) and a deck 21 ft wide.

Who owns 300th ST over Miners Creek?

It is owned by the County Highway Agency.