US Bridges

31390 481st Ave over Drainage Ditch

Fair

Union County, South Dakota · 10.1N & 5E Elk Point · Structure no. 000000064110169

Built
1976
49 years old
Condition
Fair
inspected August 2024
Type
Tee Beam
Prestressed Concrete
Length
101 ft
3 main spans
Daily traffic
140
2022 count
Owner
County
County Highway Agency

About this bridge

31390 481st Ave over Drainage Ditch is a prestressed concrete tee beam carrying 31390 481st Ave over Drainage Ditch in Union County, South Dakota. It was built in 1976, so it is 49 years old, older than the South Dakota average of 48.9 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 140 vehicles a day, roughly 2% of them trucks, projected to reach 140 by 2032. The structure is 101 ft (30.7 m) long and 31 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

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Carries31390 481st Ave
CrossesDrainage Ditch
Location10.1N & 5E Elk Point
RouteCounty Highway 0
CountyUnion County
StateSouth Dakota
Coordinates42.8372, -96.58659
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.
Superstructure8 Very GoodNo problems noted.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionAugust 2024
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 alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating36 US tons
Inventory rating27 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans3
Design loadUnknown
Structure length101 ft (30.7 m)
Longest span40 ft (12.2 m)
Deck width31 ft (9.4 m)
Roadway width30 ft (9.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic140 (2022)
Projected traffic140 by 2032
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 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$25,000
NavigationNo navigation control on waterway

Frequently asked questions

When was 31390 481st Ave over Drainage Ditch built?

It was built in 1976, making it 49 years old in 2025.

What condition is 31390 481st Ave over Drainage Ditch 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 2024.

How much traffic does 31390 481st Ave over Drainage Ditch carry?

About 140 vehicles per day (2022 count), of which roughly 2% are trucks.

How long is 31390 481st Ave over Drainage Ditch?

The structure is 101 ft (30.7 m) long with a longest span of 40 ft (12.2 m) and a deck 31 ft wide.

Who owns 31390 481st Ave over Drainage Ditch?

It is owned by the County Highway Agency.