US Bridges

Hemlock Trail over Blackbird CR

Fair

Putnam County, Missouri · S 4 T 64 N R 17 W · Structure no. 20473

Built
1991
34 years old
Condition
Fair
inspected February 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
122 ft
3 main spans
Daily traffic
10
2024 count
Owner
County
County Highway Agency

About this bridge

Hemlock Trail over Blackbird CR is a steel stringer/multi-beam or girder carrying Hemlock Trail over Blackbird CR in Putnam County, Missouri. It was built in 1991, so it is 34 years old, younger 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 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 10 vehicles a day, roughly 10% of them trucks, projected to reach 11 by 2044. The structure is 122 ft (37.2 m) long and 17 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

Location

Open in Google Maps
CarriesHemlock Trail
CrossesBlackbird CR
LocationS 4 T 64 N R 17 W
RouteCounty Highway 261
CountyPutnam County
StateMissouri
Coordinates40.38147, -92.81546
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating40.7 US tons
Inventory rating27.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckWood or timber
Main spans3
Design loadOther
Structure length122 ft (37.2 m)
Longest span78 ft (23.8 m)
Deck width17 ft (5.3 m)
Roadway width16 ft (5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10 (2024)
Projected traffic11 by 2044
Trucks10%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.8 mi (11 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 proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$570,000 (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Hemlock Trail over Blackbird CR built?

It was built in 1991, making it 34 years old in 2025.

What condition is Hemlock Trail over 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 February 2023.

How much traffic does Hemlock Trail over Blackbird CR carry?

About 10 vehicles per day (2024 count), of which roughly 10% are trucks.

How long is Hemlock Trail over Blackbird CR?

The structure is 122 ft (37.2 m) long with a longest span of 78 ft (23.8 m) and a deck 17 ft wide.

Who owns Hemlock Trail over Blackbird CR?

It is owned by the County Highway Agency.