US Bridges

486 Avenue over Monighan Ck

FairPosted for load

Deuel County, South Dakota · 1W & 1.5N Gary · Structure no. 000000020200114

Built
1954
71 years old
Condition
Fair
inspected August 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
149 ft
3 main spans
Daily traffic
143
2022 count
Owner
County
County Highway Agency

About this bridge

486 Avenue over Monighan Ck is a steel stringer/multi-beam or girder carrying 486 Avenue over Monighan Ck in Deuel County, South Dakota. It was built in 1954, so it is 71 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. Its operating status is: posted for load restriction.

It carries about 143 vehicles a day, roughly 3% of them trucks, projected to reach 143 by 2033. The structure is 149 ft (45.4 m) long and 26 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
Carries486 Avenue
CrossesMonighan Ck
Location1W & 1.5N Gary
RouteCounty Highway 0
CountyDeuel County
StateSouth Dakota
Coordinates44.81327, -96.4794
Functional classRural Major Collector

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection4 PoorAdvanced section loss, deterioration, spalling or scour.
Last inspectionAugust 2024
Inspection intervalevery 12 months
Operating statusPosted for load restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating26 US tons
Inventory rating15 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans3
Design loadH 15
Structure length149 ft (45.4 m)
Longest span49 ft (14.9 m)
Deck width26 ft (8 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic143 (2022)
Projected traffic143 by 2033
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.1 mi (13 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$500,000 (2023 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was 486 Avenue over Monighan Ck built?

It was built in 1954, making it 71 years old in 2025.

What condition is 486 Avenue over Monighan 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 2024.

How much traffic does 486 Avenue over Monighan Ck carry?

About 143 vehicles per day (2022 count), of which roughly 3% are trucks.

How long is 486 Avenue over Monighan Ck?

The structure is 149 ft (45.4 m) long with a longest span of 49 ft (14.9 m) and a deck 26 ft wide.

Who owns 486 Avenue over Monighan Ck?

It is owned by the County Highway Agency.