US Bridges

Knowlton Mills RD over Black Stream

Fair

Piscataquis County, Maine · 50 Ft SW Burrough RD · Structure no. 0952

Built
1968
57 years old
Condition
Fair
inspected October 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
34 ft
2 main spans
Daily traffic
92
2016 count
Owner
State
State Highway Agency

About this bridge

Knowlton Mills RD over Black Stream is a steel continuous stringer/multi-beam or girder carrying Knowlton Mills RD over Black Stream in Piscataquis County, Maine. It was built in 1968, so it is 57 years old, older than the Maine average of 53.7 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 92 vehicles a day, roughly 5% of them trucks, projected to reach 147 by 2036. The structure is 34 ft (10.3 m) long and 17 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesKnowlton Mills RD
CrossesBlack Stream
Location50 Ft SW Burrough RD
RouteCity Street 0
CountyPiscataquis County
StateMaine
Coordinates45.16025, -69.28185
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.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
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 adequacy8: Equal to present desirable criteria
Approach roadway alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating61.1 US tons
Inventory rating47.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadUnknown
Structure length34 ft (10.3 m)
Longest span16 ft (4.9 m)
Deck width17 ft (5.3 m)
Roadway width16 ft (4.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic92 (2016)
Projected traffic147 by 2036
Trucks5%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 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 Knowlton Mills RD over Black Stream built?

It was built in 1968, making it 57 years old in 2025.

What condition is Knowlton Mills RD over Black Stream 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 October 2023.

How much traffic does Knowlton Mills RD over Black Stream carry?

About 92 vehicles per day (2016 count), of which roughly 5% are trucks.

How long is Knowlton Mills RD over Black Stream?

The structure is 34 ft (10.3 m) long with a longest span of 16 ft (4.9 m) and a deck 17 ft wide.

Who owns Knowlton Mills RD over Black Stream?

It is owned by the State Highway Agency.