US Bridges

Nh 18 over Gale River

Fair

Grafton County, New Hampshire · 1.6 MI from Sugar Hill Tl · Structure no. 008700700011500

Built
1930
95 years old
Condition
Fair
inspected August 2023
Type
Girder and Floorbeam System
Steel
Length
58 ft
1 main span
Daily traffic
629
2023 count
Owner
State
State Highway Agency

About this bridge

Nh 18 over Gale River is a steel girder and floorbeam system carrying Nh 18 over Gale River in Grafton County, New Hampshire. It was built in 1930, so it is 95 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 629 vehicles a day, roughly 10% of them trucks, projected to reach 930 by 2043. The structure is 58 ft (17.7 m) long and 28 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesNh 18
CrossesGale River
Location1.6 MI from Sugar Hill Tl
RouteState Highway 18
CountyGrafton County
StateNew Hampshire
Coordinates44.21983, -71.7331
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.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 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 geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating27.7 US tons
Inventory rating24.3 US tons

Structure

Structure typeGirder and Floorbeam System
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length58 ft (17.7 m)
Longest span51 ft (15.5 m)
Deck width28 ft (8.5 m)
Roadway width25 ft (7.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic629 (2023)
Projected traffic930 by 2043
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 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 18 over Gale River built?

It was built in 1930, making it 95 years old in 2025.

What condition is Nh 18 over Gale 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 2023.

How much traffic does Nh 18 over Gale River carry?

About 629 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is Nh 18 over Gale River?

The structure is 58 ft (17.7 m) long with a longest span of 51 ft (15.5 m) and a deck 28 ft wide.

Who owns Nh 18 over Gale River?

It is owned by the State Highway Agency.