US Bridges

305th ST over Keg Creek

Poor

Harrison County, Iowa · 078411301 · Structure no. 000000000177000

Built
1957
68 years old
Condition
Poor
inspected December 2024
Type
Channel Beam
Concrete
Length
42 ft
1 main span
Daily traffic
20
2022 count
Owner
County
County Highway Agency

About this bridge

305th ST over Keg Creek is a concrete channel beam carrying 305th ST over Keg Creek in Harrison County, Iowa. It was built in 1957, so it is 68 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.

It carries about 20 vehicles a day, projected to reach 20 by 2044. The structure is 42 ft (12.8 m) long and 19 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
Carries305th ST
CrossesKeg Creek
Location078411301
RouteCounty Highway 0
CountyHarrison County
StateIowa
Coordinates41.56397, -95.51436
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 protection4 PoorAdvanced section loss, deterioration, spalling or scour.
Last inspectionDecember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating48.9 US tons
Inventory rating36 US tons

Structure

Structure typeChannel Beam
MaterialConcrete
DeckConcrete, precast panels
Main spans1
Design loadUnknown
Structure length42 ft (12.8 m)
Longest span40 ft (12.2 m)
Deck width19 ft (5.9 m)
Roadway width19 ft (5.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic20 (2022)
Projected traffic20 by 2044
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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was 305th ST over Keg Creek built?

It was built in 1957, making it 68 years old in 2025.

What condition is 305th ST over Keg 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 December 2024.

How much traffic does 305th ST over Keg Creek carry?

About 20 vehicles per day (2022 count).

How long is 305th ST over Keg Creek?

The structure is 42 ft (12.8 m) long with a longest span of 40 ft (12.2 m) and a deck 19 ft wide.

Who owns 305th ST over Keg Creek?

It is owned by the County Highway Agency.