US Bridges

Duncan over Stillwater River

FairPosted for load

Darke County, Ohio · .16 MI N Duvall · Structure no. 1951033

Built
1983
42 years old
Condition
Fair
inspected July 2024
Type
Truss - Thru
Steel
Length
87 ft
1 main span
Daily traffic
477
2015 count
Owner
County
County Highway Agency

About this bridge

Duncan over Stillwater River is a steel truss - thru carrying Duncan over Stillwater River in Darke County, Ohio. It was built in 1983, so it is 42 years old, younger than the Ohio average of 47.3 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. Its operating status is: posted for load restriction.

It carries about 477 vehicles a day, roughly 8% of them trucks, projected to reach 662 by 2035. The structure is 87 ft (26.5 m) long and 24 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesDuncan
CrossesStillwater River
Location.16 MI N Duvall
RouteCounty Highway C0156
CountyDarke County
StateOhio
Coordinates40.23825, -84.67167
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
Deck8 Very GoodNo problems noted.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2024
Inspection intervalevery 12 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating39.2 US tons
Inventory rating25 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckWood or timber
Main spans1
Design loadHS 20
Structure length87 ft (26.5 m)
Longest span85 ft (25.9 m)
Deck width24 ft (7.3 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic477 (2015)
Projected traffic662 by 2035
Trucks8%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 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 Duncan over Stillwater River built?

It was built in 1983, making it 42 years old in 2025.

What condition is Duncan over Stillwater River 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 July 2024.

How much traffic does Duncan over Stillwater River carry?

About 477 vehicles per day (2015 count), of which roughly 8% are trucks.

How long is Duncan over Stillwater River?

The structure is 87 ft (26.5 m) long with a longest span of 85 ft (25.9 m) and a deck 24 ft wide.

Who owns Duncan over Stillwater River?

It is owned by the County Highway Agency.