US Bridges

Twnshp RD 484th Av over Cobb Ck

PoorPosted for load

Deuel County, South Dakota · 3.4 S 3.0 W Gary · Structure no. 000000020180164

Built
1945
80 years old
Condition
Poor
inspected August 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
32 ft
1 main span
Daily traffic
10
2022 count
Owner
County
County Highway Agency

About this bridge

Twnshp RD 484th Av over Cobb Ck is a steel stringer/multi-beam or girder carrying Twnshp RD 484th Av over Cobb Ck in Deuel County, South Dakota. It was built in 1945, so it is 80 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 poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. Its operating status is: posted for load restriction.

It carries about 10 vehicles a day, roughly 2% of them trucks, projected to reach 10 by 2032. The structure is 32 ft (9.9 m) long and 20 ft wide.

CarriesTwnshp RD 484th Av
CrossesCobb Ck
Location3.4 S 3.0 W Gary
RouteCounty Highway 0
Coordinates44.74168, -96.52101
Functional classRural Local

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating27 US tons
Inventory rating19.8 US tons

Structure

MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length32 ft (9.9 m)
Longest span31 ft (9.4 m)
Deck width20 ft (6.2 m)
Roadway width18 ft (5.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10 (2022)
Projected traffic10 by 2032
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed—
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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Twnshp RD 484th Av over Cobb Ck built?

It was built in 1945, making it 80 years old in 2025.

What condition is Twnshp RD 484th Av over Cobb Ck in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in August 2024.

How much traffic does Twnshp RD 484th Av over Cobb Ck carry?

About 10 vehicles per day (2022 count), of which roughly 2% are trucks.

How long is Twnshp RD 484th Av over Cobb Ck?

The structure is 32 ft (9.9 m) long with a longest span of 31 ft (9.4 m) and a deck 20 ft wide.

Who owns Twnshp RD 484th Av over Cobb Ck?

It is owned by the County Highway Agency.