US Bridges

485th Avenue over Ck

Fair

Brookings County, South Dakota · 6.9N & 1W Elkton · Structure no. 000000006310141

Built
1930
95 years old
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
25 ft
1 main span
Daily traffic
92
2022 count
Owner
County
County Highway Agency

About this bridge

485th Avenue over Ck is a steel stringer/multi-beam or girder carrying 485th Avenue over Ck in Brookings County, South Dakota. It was built in 1930, so it is 95 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 92 vehicles a day, roughly 2% of them trucks, projected to reach 92 by 2032. The structure is 25 ft (7.5 m) long and 16 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

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Carries485th Avenue
CrossesCk
Location6.9N & 1W Elkton
RouteCounty Highway 0
CountyBrookings County
StateSouth Dakota
Coordinates44.33855, -96.50657
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
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 protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment6: Equal to present minimum criteria
Operating rating36.5 US tons
Inventory rating26.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckWood or timber
Main spans1
Design loadUnknown
Structure length25 ft (7.5 m)
Longest span24 ft (7.4 m)
Deck width16 ft (4.9 m)
Roadway width14 ft (4.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic92 (2022)
Projected traffic92 by 2032
Trucks2%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$741,000 (2023 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was 485th Avenue over Ck built?

It was built in 1930, making it 95 years old in 2025.

What condition is 485th Avenue over 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 September 2023.

How much traffic does 485th Avenue over Ck carry?

About 92 vehicles per day (2022 count), of which roughly 2% are trucks.

How long is 485th Avenue over Ck?

The structure is 25 ft (7.5 m) long with a longest span of 24 ft (7.4 m) and a deck 16 ft wide.

Who owns 485th Avenue over Ck?

It is owned by the County Highway Agency.