US Bridges

Nh 10 over Grant Brook

Good

Grafton County, New Hampshire · 3.1 MI from Hanover Tl · Structure no. 015700750010600

Built
1958
67 years old
Condition
Good
inspected June 2023
Type
Culvert
Concrete
Length
30 ft
1 main span
Daily traffic
2,894
2023 count
Owner
State
State Highway Agency

About this bridge

Nh 10 over Grant Brook is a concrete culvert carrying Nh 10 over Grant Brook in Grafton County, New Hampshire. It was built in 1958, so it is 67 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 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 2,894 vehicles a day, roughly 7% of them trucks, projected to reach 4,283 by 2043. The structure is 30 ft (9.1 m) long. If it were closed, the detour would be 14.9 mi (24 km).

Location

Open in Google Maps
CarriesNh 10
CrossesGrant Brook
Location3.1 MI from Hanover Tl
RouteState Highway 10
CountyGrafton County
StateNew Hampshire
Coordinates43.80728, -72.16309
Functional classRural Minor Arterial

Condition and inspection

Good

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

ComponentRatingMeaning
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Culvert7 GoodSome minor problems.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating63.1 US tons
Inventory rating45 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans1
Design loadHS 20
Structure length30 ft (9.1 m)
Longest span30 ft (9.1 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,894 (2023)
Projected traffic4,283 by 2043
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed14.9 mi (24 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 10 over Grant Brook built?

It was built in 1958, making it 67 years old in 2025.

What condition is Nh 10 over Grant Brook 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 June 2023.

How much traffic does Nh 10 over Grant Brook carry?

About 2,894 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is Nh 10 over Grant Brook?

The structure is 30 ft (9.1 m) long with a longest span of 30 ft (9.1 m).

Who owns Nh 10 over Grant Brook?

It is owned by the State Highway Agency.