US Bridges

SD020 over Thunder Butte Ck

Good

Perkins County, South Dakota · 7.7 W of Bison · Structure no. 000000053161290

Built
1983
42 years old
Condition
Good
inspected September 2024
Type
Culvert
Concrete Continuous
Length
37 ft
3 main spans
Daily traffic
408
2024 count
Owner
State
State Highway Agency

About this bridge

SD020 over Thunder Butte Ck is a concrete continuous culvert carrying SD020 over Thunder Butte Ck in Perkins County, South Dakota. It was built in 1983, so it is 42 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 good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 408 vehicles a day, roughly 22% of them trucks, projected to reach 610 by 2044. The structure is 37 ft (11.3 m) long. If it were closed, the detour would be 98.8 mi (159 km).

CarriesSD020
CrossesThunder Butte Ck
Location7.7 W of Bison
RouteState Highway 20
Coordinates45.53094, -102.61999
Functional classRural Minor Arterial

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Channel and channel protection8 Very GoodNo problems noted.
Culvert7 GoodSome minor problems.
Last inspectionSeptember 2024
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating99 US tons
Inventory rating59.1 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans3
Design loadHS 20 + Mod
Structure length37 ft (11.3 m)
Longest span12 ft (3.7 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic408 (2024)
Projected traffic610 by 2044
Trucks22%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was SD020 over Thunder Butte Ck built?

It was built in 1983, making it 42 years old in 2025.

What condition is SD020 over Thunder Butte Ck in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in September 2024.

How much traffic does SD020 over Thunder Butte Ck carry?

About 408 vehicles per day (2024 count), of which roughly 22% are trucks.

How long is SD020 over Thunder Butte Ck?

The structure is 37 ft (11.3 m) long with a longest span of 12 ft (3.7 m).

Who owns SD020 over Thunder Butte Ck?

It is owned by the State Highway Agency.