US Bridges

Mystic Road over Castle Ck

Fair

Pennington County, South Dakota · 0.5 S Mystic · Structure no. 000000052206308

Built
1980
45 years old
Condition
Fair
inspected September 2023
Type
Tee Beam
Prestressed Concrete
Length
26 ft
1 main span
Daily traffic
128
2022 count
Owner
County
County Highway Agency

About this bridge

Mystic Road over Castle Ck is a prestressed concrete tee beam carrying Mystic Road over Castle Ck in Pennington County, South Dakota. It was built in 1980, so it is 45 years old, younger 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 128 vehicles a day, roughly 7% of them trucks, projected to reach 128 by 2035. The structure is 26 ft (7.9 m) long and 27 ft wide. If it were closed, the detour would be 18 mi (29 km).

Location

Open in Google Maps
CarriesMystic Road
CrossesCastle Ck
Location0.5 S Mystic
RouteCounty Highway 0
CountyPennington County
StateSouth Dakota
Coordinates44.07199, -103.64161
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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
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 geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating66.5 US tons
Inventory rating39.8 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans1
Design loadHS 20
Structure length26 ft (7.9 m)
Longest span25 ft (7.6 m)
Deck width27 ft (8.2 m)
Roadway width27 ft (8.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic128 (2022)
Projected traffic128 by 2035
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed18 mi (29 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Mystic Road over Castle Ck built?

It was built in 1980, making it 45 years old in 2025.

What condition is Mystic Road over Castle 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 Mystic Road over Castle Ck carry?

About 128 vehicles per day (2022 count), of which roughly 7% are trucks.

How long is Mystic Road over Castle Ck?

The structure is 26 ft (7.9 m) long with a longest span of 25 ft (7.6 m) and a deck 27 ft wide.

Who owns Mystic Road over Castle Ck?

It is owned by the County Highway Agency.