US Bridges

306 Avenue over Okobojo Ck

Fair

Sully County, South Dakota · 2E & 0.8S Agar · Structure no. 000000060330048

Built
1968
57 years old
Condition
Fair
inspected August 2023
Type
Channel Beam
Concrete
Length
38 ft
1 main span
Daily traffic
25
2022 count
Owner
County
County Highway Agency

About this bridge

306 Avenue over Okobojo Ck is a concrete channel beam carrying 306 Avenue over Okobojo Ck in Sully County, South Dakota. It was built in 1968, so it is 57 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 25 vehicles a day, roughly 2% of them trucks, projected to reach 25 by 2032. The structure is 38 ft (11.6 m) long and 29 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
Carries306 Avenue
CrossesOkobojo Ck
Location2E & 0.8S Agar
RouteCounty Highway 0
CountySully County
StateSouth Dakota
Coordinates44.82582, -100.04057
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 inspectionAugust 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 alignment7: Better than present minimum criteria
Operating rating36 US tons
Inventory rating27 US tons

Structure

Structure typeChannel Beam
MaterialConcrete
DeckConcrete, precast panels
Main spans1
Design loadUnknown
Structure length38 ft (11.6 m)
Longest span36 ft (11 m)
Deck width29 ft (8.8 m)
Roadway width27 ft (8.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic25 (2022)
Projected traffic25 by 2032
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$3,000
NavigationNo navigation control on waterway

Frequently asked questions

When was 306 Avenue over Okobojo Ck built?

It was built in 1968, making it 57 years old in 2025.

What condition is 306 Avenue over Okobojo 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 August 2023.

How much traffic does 306 Avenue over Okobojo Ck carry?

About 25 vehicles per day (2022 count), of which roughly 2% are trucks.

How long is 306 Avenue over Okobojo Ck?

The structure is 38 ft (11.6 m) long with a longest span of 36 ft (11 m) and a deck 29 ft wide.

Who owns 306 Avenue over Okobojo Ck?

It is owned by the County Highway Agency.