US Bridges

Local over D.D. No 31

Fair

Calhoun County, Iowa · 088311302 · Structure no. 000000000091721

Built
1974
51 years old
Condition
Fair
inspected August 2023
Type
Slab
Concrete Continuous
Length
79 ft
3 main spans
Daily traffic
34
2022 count
Owner
County
County Highway Agency

About this bridge

Local over D.D. No 31 is a concrete continuous slab carrying Local over D.D. No 31 in Calhoun County, Iowa. It was built in 1974, so it is 51 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 34 vehicles a day, projected to reach 34 by 2043. The structure is 79 ft (24.1 m) long and 32 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
CarriesLocal
CrossesD.D. No 31
Location088311302
RouteCounty Highway 0
CountyCalhoun County
StateIowa
Coordinates42.43106, -94.41694
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
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 inspectionAugust 2023
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating57.8 US tons
Inventory rating36.4 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 20
Structure length79 ft (24.1 m)
Longest span29 ft (8.8 m)
Deck width32 ft (9.8 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic34 (2022)
Projected traffic34 by 2043
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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$30,000 (2023 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Local over D.D. No 31 built?

It was built in 1974, making it 51 years old in 2025.

What condition is Local over D.D. No 31 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 August 2023.

How much traffic does Local over D.D. No 31 carry?

About 34 vehicles per day (2022 count).

How long is Local over D.D. No 31?

The structure is 79 ft (24.1 m) long with a longest span of 29 ft (8.8 m) and a deck 32 ft wide.

Who owns Local over D.D. No 31?

It is owned by the County Highway Agency.