US Bridges

FM over Knotty Creek

Poor

Des Moines County, Iowa · 070032405 · Structure no. 000000000143211

Built
1980
45 years old
Condition
Poor
inspected September 2023
Type
Slab
Concrete Continuous
Length
116 ft
3 main spans
Daily traffic
1,019
2023 count
Owner
County
County Highway Agency

About this bridge

FM over Knotty Creek is a concrete continuous slab carrying FM over Knotty Creek in Des Moines County, Iowa. It was built in 1980, so it is 45 years old, younger than the Iowa average of 45.5 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 1,019 vehicles a day, projected to reach 1,019 by 2043. The structure is 116 ft (35.4 m) long and 32 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
CarriesFM
CrossesKnotty Creek
Location070032405
RouteCounty Highway 0
CountyDes Moines County
StateIowa
Coordinates40.85516, -91.15483
Functional classUrban Collector

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck4 PoorAdvanced section loss, deterioration, spalling or scour.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating53.2 US tons
Inventory rating32 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 20
Structure length116 ft (35.4 m)
Longest span44 ft (13.4 m)
Deck width32 ft (9.8 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,019 (2023)
Projected traffic1,019 by 2043
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.1 mi (13 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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was FM over Knotty Creek built?

It was built in 1980, making it 45 years old in 2025.

What condition is FM over Knotty Creek in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in September 2023.

How much traffic does FM over Knotty Creek carry?

About 1,019 vehicles per day (2023 count).

How long is FM over Knotty Creek?

The structure is 116 ft (35.4 m) long with a longest span of 44 ft (13.4 m) and a deck 32 ft wide.

Who owns FM over Knotty Creek?

It is owned by the County Highway Agency.