US Bridges

I-89 SB over Nh 12A

Good

Grafton County, New Hampshire · 0.5 MI from Vt S.L. · Structure no. 014400520009900

Built
2012
13 years old
Condition
Good
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
158 ft
1 main span
Daily traffic
18,618
2023 count
Owner
State
State Highway Agency

About this bridge

I-89 SB over Nh 12A is a steel stringer/multi-beam or girder carrying I-89 SB over Nh 12A in Grafton County, New Hampshire. It was built in 2012, so it is 13 years old, younger 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 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 18,618 vehicles a day, roughly 9% of them trucks, projected to reach 27,554 by 2043. The structure is 158 ft (48.2 m) long and 58 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-89 SB
CrossesNh 12A
Location0.5 MI from Vt S.L.
RouteInterstate 89
CountyGrafton County
StateNew Hampshire
Coordinates43.63148, -72.32011
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
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation8: Equal to present desirable criteria
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating82.5 US tons
Inventory rating49.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadHS 25 or greater
Structure length158 ft (48.2 m)
Longest span151 ft (46.1 m)
Deck width58 ft (17.7 m)
Roadway width54 ft (16.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic18,618 (2023)
Projected traffic27,554 by 2043
Trucks9%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate 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 Nh 12A built?

It was built in 2012, making it 13 years old in 2025.

What condition is I-89 SB over Nh 12A 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 SB over Nh 12A carry?

About 18,618 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is I-89 SB over Nh 12A?

The structure is 158 ft (48.2 m) long with a longest span of 151 ft (46.1 m) and a deck 58 ft wide.

Who owns I-89 SB over Nh 12A?

It is owned by the State Highway Agency.