US Bridges

Nh 9 Nh 31 over North Branch River

Fair

Hillsborough County, New Hampshire · 4.5 MI from Stoddard Tl · Structure no. 000901370014600

Built
1951
74 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
70 ft
1 main span
Daily traffic
7,411
2023 count
Owner
State
State Highway Agency

About this bridge

Nh 9 Nh 31 over North Branch River is a steel stringer/multi-beam or girder carrying Nh 9 Nh 31 over North Branch River in Hillsborough County, New Hampshire. It was built in 1951, so it is 74 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 7,411 vehicles a day, roughly 7% of them trucks, projected to reach 10,968 by 2043. The structure is 70 ft (21.3 m) long and 34 ft wide. If it were closed, the detour would be 8.7 mi (14 km).

Location

Open in Google Maps
CarriesNh 9 Nh 31
CrossesNorth Branch River
Location4.5 MI from Stoddard Tl
RouteState Highway 9
CountyHillsborough County
StateNew Hampshire
Coordinates43.08139, -71.9706
Functional classRural Principal Arterial - Other

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.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
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 geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating41.9 US tons
Inventory rating25 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadH 20
Structure length70 ft (21.3 m)
Longest span65 ft (19.8 m)
Deck width34 ft (10.4 m)
Roadway width31 ft (9.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,411 (2023)
Projected traffic10,968 by 2043
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed8.7 mi (14 km)
TollOn a free road
National Highway SystemYes

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 9 Nh 31 over North Branch River built?

It was built in 1951, making it 74 years old in 2025.

What condition is Nh 9 Nh 31 over North Branch 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 Nh 9 Nh 31 over North Branch River carry?

About 7,411 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is Nh 9 Nh 31 over North Branch River?

The structure is 70 ft (21.3 m) long with a longest span of 65 ft (19.8 m) and a deck 34 ft wide.

Who owns Nh 9 Nh 31 over North Branch River?

It is owned by the State Highway Agency.