US Bridges

Nh 12 over Troy Brook

Fair

Cheshire County, New Hampshire · 0.4 MI N to Keene T.L. · Structure no. 025101660017100

Built
1970
55 years old
Condition
Fair
inspected June 2024
Type
Culvert
Steel
Length
27 ft
2 main spans
Daily traffic
13,156
2023 count
Owner
State
State Highway Agency

About this bridge

Nh 12 over Troy Brook is a steel culvert carrying Nh 12 over Troy Brook in Cheshire County, New Hampshire. It was built in 1970, so it is 55 years old, younger than the New Hampshire average of 56.9 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 13,156 vehicles a day, roughly 5% of them trucks, projected to reach 19,470 by 2043. The structure is 27 ft (8.2 m) long. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesNh 12
CrossesTroy Brook
Location0.4 MI N to Keene T.L.
RouteState Highway 12
CountyCheshire County
StateNew Hampshire
Coordinates42.90647, -72.25779
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
Channel and channel protection7 GoodSome minor problems.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJune 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
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating99 US tons
Inventory rating99 US tons

Structure

Structure typeCulvert
MaterialSteel
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length27 ft (8.2 m)
Longest span11 ft (3.4 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,156 (2023)
Projected traffic19,470 by 2043
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed9.9 mi (16 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$314,000 (2025 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Nh 12 over Troy Brook built?

It was built in 1970, making it 55 years old in 2025.

What condition is Nh 12 over Troy 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 June 2024.

How much traffic does Nh 12 over Troy Brook carry?

About 13,156 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is Nh 12 over Troy Brook?

The structure is 27 ft (8.2 m) long with a longest span of 11 ft (3.4 m).

Who owns Nh 12 over Troy Brook?

It is owned by the State Highway Agency.