US Bridges

Mallow Trail over N Blackbird CR

FairPosted for load

Putnam County, Missouri · S 22 T 66 N R 18 W · Structure no. 17558

Built
1920
105 years old
Condition
Fair
inspected February 2023
Type
Truss - Thru
Steel
Length
30 ft
1 main span
Daily traffic
25
2024 count
Owner
County
County Highway Agency

About this bridge

Mallow Trail over N Blackbird CR is a steel truss - thru carrying Mallow Trail over N Blackbird CR in Putnam County, Missouri. It was built in 1920, so it is 105 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 25 vehicles a day, roughly 10% of them trucks, projected to reach 28 by 2044. The structure is 30 ft (9.1 m) long and 18 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesMallow Trail
CrossesN Blackbird CR
LocationS 22 T 66 N R 18 W
RouteCounty Highway 156
CountyPutnam County
StateMissouri
Coordinates40.50512, -92.90717
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation2: Basically intolerable, requiring high priority of replacement
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 rating14.9 US tons
Inventory rating10.9 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckWood or timber
Main spans1
Design loadOther
Structure length30 ft (9.1 m)
Longest span30 ft (9.1 m)
Deck width18 ft (5.4 m)
Roadway width18 ft (5.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic25 (2024)
Projected traffic28 by 2044
Trucks10%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$289,000 (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Mallow Trail over N Blackbird CR built?

It was built in 1920, making it 105 years old in 2025.

What condition is Mallow Trail over N 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 Mallow Trail over N Blackbird CR carry?

About 25 vehicles per day (2024 count), of which roughly 10% are trucks.

How long is Mallow Trail over N Blackbird CR?

The structure is 30 ft (9.1 m) long with a longest span of 30 ft (9.1 m) and a deck 18 ft wide.

Who owns Mallow Trail over N Blackbird CR?

It is owned by the County Highway Agency.