US Bridges

FM - 305th ST over Mosquito Creek

Fair

Harrison County, Iowa · 078411603 · Structure no. 000000000177031

Built
1978
47 years old
Condition
Fair
inspected December 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
83 ft
1 main span
Daily traffic
34
2022 count
Owner
County
County Highway Agency

About this bridge

FM - 305th ST over Mosquito Creek is a steel stringer/multi-beam or girder carrying FM - 305th ST over Mosquito Creek in Harrison County, Iowa. It was built in 1978, so it is 47 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 34 vehicles a day, projected to reach 34 by 2044. The structure is 83 ft (25.3 m) long and 32 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesFM - 305th ST
CrossesMosquito Creek
Location078411603
RouteCounty Highway 0
CountyHarrison County
StateIowa
Coordinates41.56412, -95.57143
Functional classRural Major Collector

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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionDecember 2024
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 adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating52.4 US tons
Inventory rating27.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length83 ft (25.3 m)
Longest span80 ft (24.4 m)
Deck width32 ft (9.8 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic34 (2022)
Projected traffic34 by 2044
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was FM - 305th ST over Mosquito Creek built?

It was built in 1978, making it 47 years old in 2025.

What condition is FM - 305th ST over Mosquito 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 December 2024.

How much traffic does FM - 305th ST over Mosquito Creek carry?

About 34 vehicles per day (2022 count).

How long is FM - 305th ST over Mosquito Creek?

The structure is 83 ft (25.3 m) long with a longest span of 80 ft (24.4 m) and a deck 32 ft wide.

Who owns FM - 305th ST over Mosquito Creek?

It is owned by the County Highway Agency.