US Bridges

N. 18th Ave. over Linn Creek

Good

Marshall County, Iowa · 084173000 · Structure no. 000000000363350

Built
1990
35 years old
Condition
Good
inspected July 2023
Type
Slab
Concrete Continuous
Length
235 ft
5 main spans
Daily traffic
1,783
2022 count
Owner
City
City or Municipal Highway Agency

About this bridge

N. 18th Ave. over Linn Creek is a concrete continuous slab carrying N. 18th Ave. over Linn Creek in Marshall County, Iowa. It was built in 1990, so it is 35 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 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 1,783 vehicles a day, projected to reach 1,783 by 2043. The structure is 235 ft (71.6 m) long and 67 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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CarriesN. 18th Ave.
CrossesLinn Creek
Location084173000
RouteCity Street 0
CountyMarshall County
StateIowa
Coordinates42.05247, -92.88373
Functional classUrban Minor Arterial

Condition and inspection

Good

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating83.2 US tons
Inventory rating49.9 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans5
Design loadHS 20
Structure length235 ft (71.6 m)
Longest span51 ft (15.5 m)
Deck width67 ft (20.4 m)
Roadway width54 ft (16.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,783 (2022)
Projected traffic1,783 by 2043
Trucks0%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedOther structural work, including hydraulic replacements
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was N. 18th Ave. over Linn Creek built?

It was built in 1990, making it 35 years old in 2025.

What condition is N. 18th Ave. over Linn Creek 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 July 2023.

How much traffic does N. 18th Ave. over Linn Creek carry?

About 1,783 vehicles per day (2022 count).

How long is N. 18th Ave. over Linn Creek?

The structure is 235 ft (71.6 m) long with a longest span of 51 ft (15.5 m) and a deck 67 ft wide.

Who owns N. 18th Ave. over Linn Creek?

It is owned by the City or Municipal Highway Agency.