US Bridges

Nh 16B over Great Brook

Fair

Carroll County, New Hampshire · 1.7 MI JCT 16-A · Structure no. 013201670008200

Built
1937
88 years old
Condition
Fair
inspected June 2023
Type
Slab
Concrete
Length
28 ft
1 main span
Daily traffic
464
2023 count
Owner
State
State Highway Agency

About this bridge

Nh 16B over Great Brook is a concrete slab carrying Nh 16B over Great Brook in Carroll County, New Hampshire. It was built in 1937, so it is 88 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 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 464 vehicles a day, roughly 10% of them trucks, projected to reach 686 by 2043. The structure is 28 ft (8.5 m) long and 36 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesNh 16B
CrossesGreat Brook
Location1.7 MI JCT 16-A
RouteState Highway 16B
CountyCarroll County
StateNew Hampshire
Coordinates44.16507, -71.16551
Functional classRural Minor 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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJune 2023
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 geometry6: Equal to present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating47.3 US tons
Inventory rating25.2 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length28 ft (8.5 m)
Longest span24 ft (7.3 m)
Deck width36 ft (10.9 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic464 (2023)
Projected traffic686 by 2043
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 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 16B over Great Brook built?

It was built in 1937, making it 88 years old in 2025.

What condition is Nh 16B 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 June 2023.

How much traffic does Nh 16B over Great Brook carry?

About 464 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is Nh 16B over Great Brook?

The structure is 28 ft (8.5 m) long with a longest span of 24 ft (7.3 m) and a deck 36 ft wide.

Who owns Nh 16B over Great Brook?

It is owned by the State Highway Agency.