US Bridges

170th ST over Br N Blackbird CR

Good

Putnam County, Missouri · S 28 T 66 N R 18 W · Structure no. 35077

Built
2015
10 years old
Condition
Good
inspected March 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
50 ft
1 main span
Daily traffic
5
2024 count
Owner
County
County Highway Agency

About this bridge

170th ST over Br N Blackbird CR is a steel stringer/multi-beam or girder carrying 170th ST over Br N Blackbird CR in Putnam County, Missouri. It was built in 2015, so it is 10 years old, younger than the Missouri average of 45.1 years.

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

It carries about 5 vehicles a day, roughly 10% of them trucks, projected to reach 6 by 2044. The structure is 50 ft (15.2 m) long and 18 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

Open in Google Maps
Carries170th ST
CrossesBr N Blackbird CR
LocationS 28 T 66 N R 18 W
RouteCounty Highway 156
CountyPutnam County
StateMissouri
Coordinates40.48672, -92.93452
Functional classRural Local

Condition and inspection

Good

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

ComponentRatingMeaning
Deck9 ExcellentNo problems noted.
Superstructure9 ExcellentNo problems noted.
Substructure9 ExcellentNo problems noted.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation9: Superior to present desirable criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating90.3 US tons
Inventory rating53.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length50 ft (15.2 m)
Longest span50 ft (15.2 m)
Deck width18 ft (5.5 m)
Roadway width17 ft (5.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5 (2024)
Projected traffic6 by 2044
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty 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 170th ST over Br N Blackbird CR built?

It was built in 2015, making it 10 years old in 2025.

What condition is 170th ST over Br N Blackbird CR 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 March 2023.

How much traffic does 170th ST over Br N Blackbird CR carry?

About 5 vehicles per day (2024 count), of which roughly 10% are trucks.

How long is 170th ST over Br N Blackbird CR?

The structure is 50 ft (15.2 m) long with a longest span of 50 ft (15.2 m) and a deck 18 ft wide.

Who owns 170th ST over Br N Blackbird CR?

It is owned by the County Highway Agency.