US Bridges

I-93 NB over Pemigewasset River

Fair

Grafton County, New Hampshire · Holderness-Plymouth Tl · Structure no. 021601470014100

Built
1964
61 years old, rebuilt 1993
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
425 ft
3 main spans
Daily traffic
11,461
2023 count
Owner
State
State Highway Agency

About this bridge

I-93 NB over Pemigewasset River is a steel continuous stringer/multi-beam or girder carrying I-93 NB over Pemigewasset River in Grafton County, New Hampshire. It was built in 1964 and reconstructed in 1993, so it is 61 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 11,461 vehicles a day, roughly 9% of them trucks, projected to reach 16,962 by 2043. The structure is 425 ft (129.5 m) long and 44 ft wide. If it were closed, the detour would be 11.2 mi (18 km).

Location

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CarriesI-93 NB
CrossesPemigewasset River
LocationHolderness-Plymouth Tl
RouteInterstate 93
CountyGrafton County
StateNew Hampshire
Coordinates43.76654, -71.68072
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.
Substructure7 GoodSome minor problems.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.7 US tons
Inventory rating35.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length425 ft (129.5 m)
Longest span160 ft (48.8 m)
Deck width44 ft (13.3 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11,461 (2023)
Projected traffic16,962 by 2043
Trucks9%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
Detour if closed11.2 mi (18 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)
NavigationNo navigation control on waterway

Frequently asked questions

When was I-93 NB over Pemigewasset River built?

It was built in 1964, making it 61 years old in 2025. It was reconstructed in 1993.

What condition is I-93 NB over Pemigewasset 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 August 2023.

How much traffic does I-93 NB over Pemigewasset River carry?

About 11,461 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is I-93 NB over Pemigewasset River?

The structure is 425 ft (129.5 m) long with a longest span of 160 ft (48.8 m) and a deck 44 ft wide.

Who owns I-93 NB over Pemigewasset River?

It is owned by the State Highway Agency.