US Bridges

US 3 over West Branch Brook

Fair

Grafton County, New Hampshire · 0.6 MI from Thornton Tl · Structure no. 003501170013500

Built
1927
98 years old
Condition
Fair
inspected August 2023
Type
Girder and Floorbeam System
Steel
Length
91 ft
1 main span
Daily traffic
1,054
2023 count
Owner
State
State Highway Agency

About this bridge

US 3 over West Branch Brook is a steel girder and floorbeam system carrying US 3 over West Branch Brook in Grafton County, New Hampshire. It was built in 1927, so it is 98 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 1,054 vehicles a day, roughly 4% of them trucks, projected to reach 1,559 by 2043. The structure is 91 ft (27.7 m) long and 27 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesUS 3
CrossesWest Branch Brook
Location0.6 MI from Thornton Tl
RouteU.S. Route 3
CountyGrafton County
StateNew Hampshire
Coordinates43.85138, -71.6669
Functional classRural Major 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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
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 adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating46.4 US tons
Inventory rating30.1 US tons

Structure

Structure typeGirder and Floorbeam System
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length91 ft (27.7 m)
Longest span85 ft (25.9 m)
Deck width27 ft (8.1 m)
Roadway width25 ft (7.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,054 (2023)
Projected traffic1,559 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemNo
Strategic Highway NetworkInterstate STRAHNET route

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 US 3 over West Branch Brook built?

It was built in 1927, making it 98 years old in 2025.

What condition is US 3 over West Branch Brook 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 US 3 over West Branch Brook carry?

About 1,054 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is US 3 over West Branch Brook?

The structure is 91 ft (27.7 m) long with a longest span of 85 ft (25.9 m) and a deck 27 ft wide.

Who owns US 3 over West Branch Brook?

It is owned by the State Highway Agency.