US Bridges

Nh 11B over Gunstock River

Good

Belknap County, New Hampshire · 0.2 MI E Nh RTE 11 · Structure no. 009100990009900

Built
1970
55 years old
Condition
Good
inspected May 2023
Type
Frame
Concrete Continuous
Length
32 ft
2 main spans
Daily traffic
3,736
2023 count
Owner
State
State Highway Agency

About this bridge

Nh 11B over Gunstock River is a concrete continuous frame carrying Nh 11B over Gunstock River in Belknap 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 good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 3,736 vehicles a day, roughly 10% of them trucks, projected to reach 5,529 by 2043. The structure is 32 ft (9.8 m) long and 35 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

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CarriesNh 11B
CrossesGunstock River
Location0.2 MI E Nh RTE 11
RouteState Highway 11B
CountyBelknap County
StateNew Hampshire
Coordinates43.57863, -71.40387
Functional classUrban Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating62.8 US tons
Inventory rating37.6 US tons

Structure

Structure typeFrame
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length32 ft (9.8 m)
Longest span14 ft (4.3 m)
Deck width35 ft (10.7 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,736 (2023)
Projected traffic5,529 by 2043
Trucks10%
Lanes on structure2
Traffic directionTwo-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 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 11B over Gunstock River built?

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

What condition is Nh 11B over Gunstock River in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in May 2023.

How much traffic does Nh 11B over Gunstock River carry?

About 3,736 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is Nh 11B over Gunstock River?

The structure is 32 ft (9.8 m) long with a longest span of 14 ft (4.3 m) and a deck 35 ft wide.

Who owns Nh 11B over Gunstock River?

It is owned by the State Highway Agency.