US Bridges

SR-121 over Swamp Creek

Good

Darke County, Ohio · .83MI.W. of Jct. SR-185 · Structure no. 1902229

Built
1961
64 years old, rebuilt 2007
Condition
Good
inspected May 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
160 ft
3 main spans
Daily traffic
3,344
2015 count
Owner
State
State Highway Agency

About this bridge

SR-121 over Swamp Creek is a steel continuous stringer/multi-beam or girder carrying SR-121 over Swamp Creek in Darke County, Ohio. It was built in 1961 and reconstructed in 2007, so it is 64 years old, older than the Ohio average of 47.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 3,344 vehicles a day, roughly 3% of them trucks, projected to reach 4,641 by 2035. The structure is 160 ft (48.9 m) long and 36 ft wide. If it were closed, the detour would be 8.7 mi (14 km).

Location

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CarriesSR-121
CrossesSwamp Creek
Location.83MI.W. of Jct. SR-185
RouteState Highway 121
CountyDarke County
StateOhio
Coordinates40.21268, -84.49911
Functional classRural Major Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
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 rating44.3 US tons
Inventory rating34 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length160 ft (48.9 m)
Longest span60 ft (18.3 m)
Deck width36 ft (11 m)
Roadway width36 ft (11 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,344 (2015)
Projected traffic4,641 by 2035
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.7 mi (14 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—
NavigationNo navigation control on waterway

Frequently asked questions

When was SR-121 over Swamp Creek built?

It was built in 1961, making it 64 years old in 2025. It was reconstructed in 2007.

What condition is SR-121 over Swamp Creek in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in May 2023.

How much traffic does SR-121 over Swamp Creek carry?

About 3,344 vehicles per day (2015 count), of which roughly 3% are trucks.

How long is SR-121 over Swamp Creek?

The structure is 160 ft (48.9 m) long with a longest span of 60 ft (18.3 m) and a deck 36 ft wide.

Who owns SR-121 over Swamp Creek?

It is owned by the State Highway Agency.