US Bridges

I-89 SB over US 4 Nh 10

Fair

Grafton County, New Hampshire · 2.6 MI from Vt S.L. · Structure no. 014400940010800

Built
1966
59 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
115 ft
1 main span
Daily traffic
19,997
2023 count
Owner
State
State Highway Agency

About this bridge

I-89 SB over US 4 Nh 10 is a steel stringer/multi-beam or girder carrying I-89 SB over US 4 Nh 10 in Grafton County, New Hampshire. It was built in 1966, 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 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 19,997 vehicles a day, roughly 9% of them trucks, projected to reach 29,595 by 2043. The structure is 115 ft (35.1 m) long and 42 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI-89 SB
CrossesUS 4 Nh 10
Location2.6 MI from Vt S.L.
RouteInterstate 89
CountyGrafton County
StateNew Hampshire
Coordinates43.63786, -72.28077
Functional classUrban Principal Arterial - Interstate

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.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating58 US tons
Inventory rating35.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length115 ft (35.1 m)
Longest span108 ft (32.9 m)
Deck width42 ft (12.9 m)
Roadway width37 ft (11.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic19,997 (2023)
Projected traffic29,595 by 2043
Trucks9%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 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 SB over US 4 Nh 10 built?

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

What condition is I-89 SB over US 4 Nh 10 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 I-89 SB over US 4 Nh 10 carry?

About 19,997 vehicles per day (2023 count), of which roughly 9% are trucks.

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

The structure is 115 ft (35.1 m) long with a longest span of 108 ft (32.9 m) and a deck 42 ft wide.

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

It is owned by the State Highway Agency.