US Bridges

Mo 129 S over S Blackbird CR

FairPosted for load

Putnam County, Missouri · S 27 T 65 N R 18 W · Structure no. 8456

Built
1965
60 years old
Condition
Fair
inspected December 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
168 ft
3 main spans
Daily traffic
125
2024 count
Owner
State
State Highway Agency

About this bridge

Mo 129 S over S Blackbird CR is a steel continuous stringer/multi-beam or girder carrying Mo 129 S over S Blackbird CR in Putnam County, Missouri. It was built in 1965, so it is 60 years old, older than the Missouri average of 45.1 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 125 vehicles a day, roughly 16% of them trucks, projected to reach 156 by 2044. The structure is 168 ft (51.2 m) long and 28 ft wide. If it were closed, the detour would be 21.1 mi (34 km).

Location

Open in Google Maps
CarriesMo 129 S
CrossesS Blackbird CR
LocationS 27 T 65 N R 18 W
RouteState Highway 129
CountyPutnam County
StateMissouri
Coordinates40.41474, -92.90758
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
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 adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating25.8 US tons
Inventory rating14.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadH 15
Structure length168 ft (51.2 m)
Longest span65 ft (19.8 m)
Deck width28 ft (8.4 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic125 (2024)
Projected traffic156 by 2044
Trucks16%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed21.1 mi (34 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Mo 129 S over S Blackbird CR built?

It was built in 1965, making it 60 years old in 2025.

What condition is Mo 129 S over S Blackbird CR 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 December 2023.

How much traffic does Mo 129 S over S Blackbird CR carry?

About 125 vehicles per day (2024 count), of which roughly 16% are trucks.

How long is Mo 129 S over S Blackbird CR?

The structure is 168 ft (51.2 m) long with a longest span of 65 ft (19.8 m) and a deck 28 ft wide.

Who owns Mo 129 S over S Blackbird CR?

It is owned by the State Highway Agency.