US Bridges

US085 over Buffalo Ck

Fair

Harding County, South Dakota · 2.9 S JCT Sd 20 E · Structure no. 000000032250300

Built
1964
61 years old
Condition
Fair
inspected May 2024
Type
Slab
Concrete Continuous
Length
106 ft
5 main spans
Daily traffic
1,330
2024 count
Owner
State
State Highway Agency

About this bridge

US085 over Buffalo Ck is a concrete continuous slab carrying US085 over Buffalo Ck in Harding County, South Dakota. It was built in 1964, so it is 61 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 1,330 vehicles a day, roughly 21% of them trucks, projected to reach 1,744 by 2044. The structure is 106 ft (32.2 m) long and 34 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

CarriesUS085
CrossesBuffalo Ck
Location2.9 S JCT Sd 20 E
RouteU.S. Route 85
Coordinates45.51683, -103.54574
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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating79.5 US tons
Inventory rating47.6 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans5
Design loadHS 20
Structure length106 ft (32.2 m)
Longest span21 ft (6.3 m)
Deck width34 ft (10.5 m)
Roadway width30 ft (9.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,330 (2024)
Projected traffic1,744 by 2044
Trucks21%
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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was US085 over Buffalo Ck built?

It was built in 1964, making it 61 years old in 2025.

What condition is US085 over Buffalo Ck 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 May 2024.

How much traffic does US085 over Buffalo Ck carry?

About 1,330 vehicles per day (2024 count), of which roughly 21% are trucks.

How long is US085 over Buffalo Ck?

The structure is 106 ft (32.2 m) long with a longest span of 21 ft (6.3 m) and a deck 34 ft wide.

Who owns US085 over Buffalo Ck?

It is owned by the State Highway Agency.