US Bridges

Nh 12A over Great Brook

Fair

Sullivan County, New Hampshire · 1.0 MI from Charlestown T · Structure no. 014301170010100

Built
1949
76 years old, rebuilt 1988
Condition
Fair
inspected May 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
55 ft
1 main span
Daily traffic
957
2023 count
Owner
State
State Highway Agency

About this bridge

Nh 12A over Great Brook is a steel stringer/multi-beam or girder carrying Nh 12A over Great Brook in Sullivan County, New Hampshire. It was built in 1949 and reconstructed in 1988, so it is 76 years old, older 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 6 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 957 vehicles a day, roughly 4% of them trucks, projected to reach 1,416 by 2043. The structure is 55 ft (16.8 m) long and 35 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

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CarriesNh 12A
CrossesGreat Brook
Location1.0 MI from Charlestown T
RouteState Highway 12A
CountySullivan County
StateNew Hampshire
Coordinates43.16519, -72.39086
Functional classRural Major Collector

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating69.1 US tons
Inventory rating41.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 25 or greater
Structure length55 ft (16.8 m)
Longest span48 ft (14.6 m)
Deck width35 ft (10.7 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic957 (2023)
Projected traffic1,416 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 km)
TollOn a free road
National Highway SystemNo

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 12A over Great Brook built?

It was built in 1949, making it 76 years old in 2025. It was reconstructed in 1988.

What condition is Nh 12A over Great 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 May 2024.

How much traffic does Nh 12A over Great Brook carry?

About 957 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Nh 12A over Great Brook?

The structure is 55 ft (16.8 m) long with a longest span of 48 ft (14.6 m) and a deck 35 ft wide.

Who owns Nh 12A over Great Brook?

It is owned by the State Highway Agency.