US Bridges

US 3 over Cone Brook

Fair

Coos County, New Hampshire · 3.7 MI NE Stratford Tl · Structure no. 005100590008900

Built
1952
73 years old
Condition
Fair
inspected April 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
43 ft
1 main span
Daily traffic
2,758
2023 count
Owner
State
State Highway Agency

About this bridge

US 3 over Cone Brook is a steel stringer/multi-beam or girder carrying US 3 over Cone Brook in Coos County, New Hampshire. It was built in 1952, so it is 73 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 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 2,758 vehicles a day, roughly 7% of them trucks, projected to reach 4,081 by 2043. The structure is 43 ft (13.1 m) long and 35 ft wide. If it were closed, the detour would be 14.9 mi (24 km).

Location

Open in Google Maps
CarriesUS 3
CrossesCone Brook
Location3.7 MI NE Stratford Tl
RouteU.S. Route 3
CountyCoos County
StateNew Hampshire
Coordinates44.81756, -71.56761
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
Deck7 GoodSome minor problems.
Superstructure8 Very GoodNo problems noted.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionApril 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
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 rating46.1 US tons
Inventory rating27.4 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadH 20
Structure length43 ft (13.1 m)
Longest span36 ft (11 m)
Deck width35 ft (10.7 m)
Roadway width32 ft (9.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,758 (2023)
Projected traffic4,081 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 US 3 over Cone Brook built?

It was built in 1952, making it 73 years old in 2025.

What condition is US 3 over Cone 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 April 2024.

How much traffic does US 3 over Cone Brook carry?

About 2,758 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is US 3 over Cone Brook?

The structure is 43 ft (13.1 m) long with a longest span of 36 ft (11 m) and a deck 35 ft wide.

Who owns US 3 over Cone Brook?

It is owned by the State Highway Agency.