US Bridges

Base Station Road over Ammonoosuc River

Fair

Coos County, New Hampshire · 4.3 MI NE US302 · Structure no. 005550900018200

Built
1937
88 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
62 ft
1 main span
Daily traffic
1,793
2023 count
Owner
State
State Highway Agency

About this bridge

Base Station Road over Ammonoosuc River is a steel stringer/multi-beam or girder carrying Base Station Road over Ammonoosuc River in Coos County, New Hampshire. It was built in 1937, so it is 88 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 1,793 vehicles a day, roughly 10% of them trucks, projected to reach 2,653 by 2043. The structure is 62 ft (18.9 m) long and 28 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesBase Station Road
CrossesAmmonoosuc River
Location4.3 MI NE US302
RouteState Highway 0
CountyCoos County
StateNew Hampshire
Coordinates44.26286, -71.38499
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection4 PoorAdvanced section loss, deterioration, spalling or scour.
Last inspectionJune 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 adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating43.9 US tons
Inventory rating26.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length62 ft (18.9 m)
Longest span59 ft (18 m)
Deck width28 ft (8.4 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,793 (2023)
Projected traffic2,653 by 2043
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 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 Base Station Road over Ammonoosuc River built?

It was built in 1937, making it 88 years old in 2025.

What condition is Base Station Road over 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 Base Station Road over Ammonoosuc River carry?

About 1,793 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is Base Station Road over Ammonoosuc River?

The structure is 62 ft (18.9 m) long with a longest span of 59 ft (18 m) and a deck 28 ft wide.

Who owns Base Station Road over Ammonoosuc River?

It is owned by the State Highway Agency.