US Bridges

I-89 Nh 10 NB over US 4

Good

Grafton County, New Hampshire · 3.0 MI from Enfield T.L. · Structure no. 014401600010500

Built
1966
59 years old, rebuilt 1986
Condition
Good
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
184 ft
3 main spans
Daily traffic
16,261
2023 count
Owner
State
State Highway Agency

About this bridge

I-89 Nh 10 NB over US 4 is a steel continuous stringer/multi-beam or girder carrying I-89 Nh 10 NB over US 4 in Grafton County, New Hampshire. It was built in 1966 and reconstructed in 1986, so it is 59 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 good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 16,261 vehicles a day, roughly 9% of them trucks, projected to reach 24,066 by 2043. The structure is 184 ft (56.1 m) long and 44 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesI-89 Nh 10 NB
CrossesUS 4
Location3.0 MI from Enfield T.L.
RouteInterstate 89
CountyGrafton County
StateNew Hampshire
Coordinates43.63533, -72.21191
Functional classUrban Principal Arterial - Interstate

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating52.6 US tons
Inventory rating31.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length184 ft (56.1 m)
Longest span77 ft (23.5 m)
Deck width44 ft (13.3 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic16,261 (2023)
Projected traffic24,066 by 2043
Trucks9%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkNon-Interstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$314,000 (2025 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-89 Nh 10 NB over US 4 built?

It was built in 1966, making it 59 years old in 2025. It was reconstructed in 1986.

What condition is I-89 Nh 10 NB over US 4 in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in June 2023.

How much traffic does I-89 Nh 10 NB over US 4 carry?

About 16,261 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is I-89 Nh 10 NB over US 4?

The structure is 184 ft (56.1 m) long with a longest span of 77 ft (23.5 m) and a deck 44 ft wide.

Who owns I-89 Nh 10 NB over US 4?

It is owned by the State Highway Agency.