US Bridges

FM (70th St) over Dd No. 6

Fair

Franklin County, Iowa · 090211101 · Structure no. 000000000156661

Built
1956
69 years old, rebuilt 2007
Condition
Fair
inspected May 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
45 ft
1 main span
Daily traffic
570
2022 count
Owner
County
County Highway Agency

About this bridge

FM (70th St) over Dd No. 6 is a prestressed concrete stringer/multi-beam or girder carrying FM (70th St) over Dd No. 6 in Franklin County, Iowa. It was built in 1956 and reconstructed in 2007, so it is 69 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 570 vehicles a day, roughly 23% of them trucks, projected to reach 570 by 2043. The structure is 45 ft (13.7 m) long and 30 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesFM (70th St)
CrossesDd No. 6
Location090211101
RouteCounty Highway 0
CountyFranklin County
StateIowa
Coordinates42.63014, -93.29139
Functional classRural Major 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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating56.3 US tons
Inventory rating36.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 20
Structure length45 ft (13.7 m)
Longest span43 ft (13.1 m)
Deck width30 ft (9.1 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic570 (2022)
Projected traffic570 by 2043
Trucks23%
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 proposedOther structural work, including hydraulic replacements
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was FM (70th St) over Dd No. 6 built?

It was built in 1956, making it 69 years old in 2025. It was reconstructed in 2007.

What condition is FM (70th St) over Dd No. 6 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 May 2023.

How much traffic does FM (70th St) over Dd No. 6 carry?

About 570 vehicles per day (2022 count), of which roughly 23% are trucks.

How long is FM (70th St) over Dd No. 6?

The structure is 45 ft (13.7 m) long with a longest span of 43 ft (13.1 m) and a deck 30 ft wide.

Who owns FM (70th St) over Dd No. 6?

It is owned by the County Highway Agency.