US Bridges

IRR US012 over Missouri Rv (oahe Lk)

Fair

Walworth County, South Dakota · Corson - Walworth CO LN · Structure no. 000000065000020

Built
1959
66 years old, rebuilt 1980
Condition
Fair
inspected September 2024
Type
Truss - Thru
Steel Continuous
Length
5,058 ft
5 main spans
Daily traffic
2,071
2024 count
Owner
State
State Highway Agency

About this bridge

IRR US012 over Missouri Rv (oahe Lk) is a steel continuous truss - thru carrying IRR US012 over Missouri Rv (oahe Lk) in Walworth County, South Dakota. It was built in 1959 and reconstructed in 1980, so it is 66 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 5 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 2,071 vehicles a day, roughly 12% of them trucks, projected to reach 2,705 by 2044. The structure is 5,058 ft (1,541.8 m) long and 29 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesIRR US012
CrossesMissouri Rv (oahe Lk)
LocationCorson - Walworth CO LN
RouteU.S. Route 12
CountyWalworth County
StateSouth Dakota
Coordinates45.56114, -100.46131
Functional classRural Principal Arterial - Other

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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2024
Inspection intervalevery 12 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating57.4 US tons
Inventory rating34.4 US tons

Structure

Structure typeTruss - Thru
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans5 (+18 approach)
Design loadH 20
Structure length5,058 ft (1,541.8 m)
Longest span450 ft (137.1 m)
Deck width29 ft (8.7 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deck17 ft (5.3 m)

Traffic and service

Average daily traffic2,071 (2024)
Projected traffic2,705 by 2044
Trucks12%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$25 million
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was IRR US012 over Missouri Rv (oahe Lk) built?

It was built in 1959, making it 66 years old in 2025. It was reconstructed in 1980.

What condition is IRR US012 over Missouri Rv (oahe Lk) 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 September 2024.

How much traffic does IRR US012 over Missouri Rv (oahe Lk) carry?

About 2,071 vehicles per day (2024 count), of which roughly 12% are trucks.

How long is IRR US012 over Missouri Rv (oahe Lk)?

The structure is 5,058 ft (1,541.8 m) long with a longest span of 450 ft (137.1 m) and a deck 29 ft wide.

Who owns IRR US012 over Missouri Rv (oahe Lk)?

It is owned by the State Highway Agency.