US Bridges

490th ST over Montgomery Creek

Fair

Clay County, Iowa · 094353001 · Structure no. 000000000115751

Built
1990
35 years old
Condition
Fair
inspected March 2023
Type
Slab
Concrete
Length
33 ft
1 main span
Daily traffic
46
2022 count
Owner
County
County Highway Agency

About this bridge

490th ST over Montgomery Creek is a concrete slab carrying 490th ST over Montgomery Creek in Clay 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 fair condition with a lowest component rating of 5 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 46 vehicles a day, projected to reach 46 by 2043. The structure is 33 ft (10.1 m) long and 32 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
Carries490th ST
CrossesMontgomery Creek
Location094353001
RouteCounty Highway 0
CountyClay County
StateIowa
Coordinates42.93876, -95.02603
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry7: Better than present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating65.5 US tons
Inventory rating36 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 20
Structure length33 ft (10.1 m)
Longest span30 ft (9.1 m)
Deck width32 ft (9.8 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic46 (2022)
Projected traffic46 by 2043
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 490th ST over Montgomery Creek built?

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

What condition is 490th ST over Montgomery 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 March 2023.

How much traffic does 490th ST over Montgomery Creek carry?

About 46 vehicles per day (2022 count).

How long is 490th ST over Montgomery Creek?

The structure is 33 ft (10.1 m) long with a longest span of 30 ft (9.1 m) and a deck 32 ft wide.

Who owns 490th ST over Montgomery Creek?

It is owned by the County Highway Agency.