US Bridges

N18 340th Ave over Lost Island Lake

Good

Clay County, Iowa · 096350105 · Structure no. 000000000116471

Built
2021
4 years old
Condition
Good
inspected December 2022
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
58 ft
1 main span
Daily traffic
838
2022 count
Owner
County
County Highway Agency

About this bridge

N18 340th Ave over Lost Island Lake is a prestressed concrete stringer/multi-beam or girder carrying N18 340th Ave over Lost Island Lake in Clay County, Iowa. It was built in 2021, so it is 4 years old, younger than the Iowa average of 45.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 838 vehicles a day, roughly 11% of them trucks, projected to reach 838 by 2043. The structure is 58 ft (17.7 m) long and 31 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesN18 340th Ave
CrossesLost Island Lake
Location096350105
RouteCounty Highway 0
CountyClay County
StateIowa
Coordinates43.16422, -94.91821
Functional classRural Major Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionDecember 2022
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating55.3 US tons
Inventory rating41.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHL 93
Structure length58 ft (17.7 m)
Longest span55 ft (16.8 m)
Deck width31 ft (9.4 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic838 (2022)
Projected traffic838 by 2043
Trucks11%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed9.9 mi (16 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 N18 340th Ave over Lost Island Lake built?

It was built in 2021, making it 4 years old in 2025.

What condition is N18 340th Ave over Lost Island Lake in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in December 2022.

How much traffic does N18 340th Ave over Lost Island Lake carry?

About 838 vehicles per day (2022 count), of which roughly 11% are trucks.

How long is N18 340th Ave over Lost Island Lake?

The structure is 58 ft (17.7 m) long with a longest span of 55 ft (16.8 m) and a deck 31 ft wide.

Who owns N18 340th Ave over Lost Island Lake?

It is owned by the County Highway Agency.