US Bridges

NH110 over Upper Ammonoosuc River

Fair

Coos County, New Hampshire · 0.9 MI from Dummer Tl · Structure no. 017000770013300

Built
1970
55 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
123 ft
1 main span
Daily traffic
1,619
2023 count
Owner
State
State Highway Agency

About this bridge

NH110 over Upper Ammonoosuc River is a steel stringer/multi-beam or girder carrying NH110 over Upper Ammonoosuc River in Coos 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 fair condition with a lowest component rating of 6 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 1,619 vehicles a day, roughly 4% of them trucks, projected to reach 2,396 by 2043. The structure is 123 ft (37.5 m) long and 47 ft wide. If it were closed, the detour would be 14.9 mi (24 km).

Location

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CarriesNH110
CrossesUpper Ammonoosuc River
Location0.9 MI from Dummer Tl
RouteState Highway 110
CountyCoos County
StateNew Hampshire
Coordinates44.5974, -71.30515
Functional classRural Minor Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating49.3 US tons
Inventory rating29.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length123 ft (37.5 m)
Longest span118 ft (36 m)
Deck width47 ft (14.2 m)
Roadway width43 ft (13 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,619 (2023)
Projected traffic2,396 by 2043
Trucks4%
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 NH110 over Upper Ammonoosuc River built?

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

What condition is NH110 over Upper Ammonoosuc 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 June 2023.

How much traffic does NH110 over Upper Ammonoosuc River carry?

About 1,619 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is NH110 over Upper Ammonoosuc River?

The structure is 123 ft (37.5 m) long with a longest span of 118 ft (36 m) and a deck 47 ft wide.

Who owns NH110 over Upper Ammonoosuc River?

It is owned by the State Highway Agency.