US Bridges

FM over Thunder Creek

Fair

Marion County, Iowa · 077182804 · Structure no. 000000000241031

Built
1975
50 years old
Condition
Fair
inspected December 2022
Type
Slab
Concrete Continuous
Length
103 ft
3 main spans
Daily traffic
330
2022 count
Owner
County
County Highway Agency

About this bridge

FM over Thunder Creek is a concrete continuous slab carrying FM over Thunder Creek in Marion County, Iowa. It was built in 1975, so it is 50 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 330 vehicles a day, projected to reach 330 by 2043. The structure is 103 ft (31.4 m) long and 32 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesFM
CrossesThunder Creek
Location077182804
RouteCounty Highway 0
CountyMarion County
StateIowa
Coordinates41.43728, -92.94798
Functional classRural Minor 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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionDecember 2022
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating54.9 US tons
Inventory rating33.1 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 20
Structure length103 ft (31.4 m)
Longest span39 ft (11.9 m)
Deck width32 ft (9.8 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic330 (2022)
Projected traffic330 by 2043
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 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 proposedOther structural work, including hydraulic replacements
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was FM over Thunder Creek built?

It was built in 1975, making it 50 years old in 2025.

What condition is FM over Thunder 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 2022.

How much traffic does FM over Thunder Creek carry?

About 330 vehicles per day (2022 count).

How long is FM over Thunder Creek?

The structure is 103 ft (31.4 m) long with a longest span of 39 ft (11.9 m) and a deck 32 ft wide.

Who owns FM over Thunder Creek?

It is owned by the County Highway Agency.