US Bridges

N Main ST over Eaton Brook

Fair

Penobscot County, Maine · .5 Mi.S. Townline · Structure no. 3316

Built
1936
89 years old, rebuilt 1991
Condition
Fair
inspected December 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
41 ft
1 main span
Daily traffic
7,669
2016 count
Owner
State
State Highway Agency

About this bridge

N Main ST over Eaton Brook is a steel stringer/multi-beam or girder carrying N Main ST over Eaton Brook in Penobscot County, Maine. It was built in 1936 and reconstructed in 1991, so it is 89 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 7,669 vehicles a day, roughly 5% of them trucks, projected to reach 10,737 by 2036. The structure is 41 ft (12.5 m) long and 44 ft wide. If it were closed, the detour would be 100 mi (161 km).

Location

Open in Google Maps
CarriesN Main ST
CrossesEaton Brook
Location.5 Mi.S. Townline
RouteState Highway 9
CountyPenobscot County
StateMaine
Coordinates44.81779, -68.70763
Functional classUrban Other Principal Arterial

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 protection7 GoodSome minor problems.
Last inspectionDecember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being 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 alignment6: Equal to present minimum criteria
Operating rating78.6 US tons
Inventory rating60.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 25 or greater
Structure length41 ft (12.5 m)
Longest span36 ft (11.1 m)
Deck width44 ft (13.4 m)
Roadway width42 ft (12.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,669 (2016)
Projected traffic10,737 by 2036
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed100 mi (161 km)
TollOn a free road
National Highway SystemYes

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 N Main ST over Eaton Brook built?

It was built in 1936, making it 89 years old in 2025. It was reconstructed in 1991.

What condition is N Main ST over Eaton Brook 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 2024.

How much traffic does N Main ST over Eaton Brook carry?

About 7,669 vehicles per day (2016 count), of which roughly 5% are trucks.

How long is N Main ST over Eaton Brook?

The structure is 41 ft (12.5 m) long with a longest span of 36 ft (11.1 m) and a deck 44 ft wide.

Who owns N Main ST over Eaton Brook?

It is owned by the State Highway Agency.