US Bridges

161 ST over I029

Fair

Codington County, South Dakota · 4 S Sd 20 Interch · Structure no. 000000015215070

Built
1974
51 years old
Condition
Fair
inspected May 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
297 ft
2 main spans
Daily traffic
77
2023 count
Owner
State
State Highway Agency

About this bridge

161 ST over I029 is a steel continuous stringer/multi-beam or girder carrying 161 ST over I029 in Codington County, South Dakota. It was built in 1974, so it is 51 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 77 vehicles a day, roughly 2% of them trucks, projected to reach 77 by 2043. The structure is 297 ft (90.4 m) long and 35 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

Open in Google Maps
Carries161 ST
CrossesI029
Location4 S Sd 20 Interch
RouteCounty Highway 0
CountyCodington County
StateSouth Dakota
Coordinates45.04955, -97.05442
Functional classRural Minor 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating63.3 US tons
Inventory rating37.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2 (+2 approach)
Design loadHS 20
Structure length297 ft (90.4 m)
Longest span112 ft (34.1 m)
Deck width35 ft (10.6 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic77 (2023)
Projected traffic77 by 2043
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway
Detour if closed8.1 mi (13 km)
TollOn a free road
National Highway SystemNo

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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was 161 ST over I029 built?

It was built in 1974, making it 51 years old in 2025.

What condition is 161 ST over I029 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 2023.

How much traffic does 161 ST over I029 carry?

About 77 vehicles per day (2023 count), of which roughly 2% are trucks.

How long is 161 ST over I029?

The structure is 297 ft (90.4 m) long with a longest span of 112 ft (34.1 m) and a deck 35 ft wide.

Who owns 161 ST over I029?

It is owned by the State Highway Agency.