SD46 over Big Sioux River
FairUnion County, South Dakota · At South Dakota Border · Structure no. 000000064160023
- Built
- 1991
- 34 years old
- Condition
- Fair
- inspected October 2023
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 518 ft
- 6 main spans
- Daily traffic
- 1,610
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
SD46 over Big Sioux River is a prestressed concrete stringer/multi-beam or girder carrying SD46 over Big Sioux River in Union County, South Dakota. It was built in 1991, so it is 34 years old, younger 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 1,610 vehicles a day, roughly 24% of them trucks, projected to reach 2,495 by 2043. The structure is 518 ft (157.9 m) long and 43 ft wide. If it were closed, the detour would be 3.7 mi (6 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 6 Satisfactory | Structural elements show some minor deterioration. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 7 Good | Some minor problems. |
| Channel and channel protection | 7 Good | Some minor problems. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was SD46 over Big Sioux River built?
It was built in 1991, making it 34 years old in 2025.
What condition is SD46 over Big Sioux River 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 October 2023.
How much traffic does SD46 over Big Sioux River carry?
About 1,610 vehicles per day (2023 count), of which roughly 24% are trucks.
How long is SD46 over Big Sioux River?
The structure is 518 ft (157.9 m) long with a longest span of 97 ft (29.6 m) and a deck 43 ft wide.
Who owns SD46 over Big Sioux River?
It is owned by the State Highway Agency.