US Bridges

Henderson Road over Gunstock River

Fair

Belknap County, New Hampshire · 0.09 MI FR Intervale RD · Structure no. 009101170010100

Built
1960
65 years old
Condition
Fair
inspected August 2024
Type
Tee Beam
Prestressed Concrete
Length
24 ft
1 main span
Daily traffic
486
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Henderson Road over Gunstock River is a prestressed concrete tee beam carrying Henderson Road over Gunstock River in Belknap County, New Hampshire. It was built in 1960, so it is 65 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 486 vehicles a day, roughly 4% of them trucks, projected to reach 719 by 2043. The structure is 24 ft (7.3 m) long and 26 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesHenderson Road
CrossesGunstock River
Location0.09 MI FR Intervale RD
CountyBelknap County
StateNew Hampshire
Coordinates43.5666, -71.39894
Functional classUrban Local

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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
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 inspectionAugust 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 geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating56.5 US tons
Inventory rating36 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 20
Structure length24 ft (7.3 m)
Longest span22 ft (6.7 m)
Deck width26 ft (8 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic486 (2023)
Projected traffic719 by 2043
Trucks4%
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

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal 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 Henderson Road over Gunstock River built?

It was built in 1960, making it 65 years old in 2025.

What condition is Henderson Road over Gunstock River 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 August 2024.

How much traffic does Henderson Road over Gunstock River carry?

About 486 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Henderson Road over Gunstock River?

The structure is 24 ft (7.3 m) long with a longest span of 22 ft (6.7 m) and a deck 26 ft wide.

Who owns Henderson Road over Gunstock River?

It is owned by the City or Municipal Highway Agency.