US Bridges

I-93 NB over NH175A

Fair

Grafton County, New Hampshire · 1.0 MI Ashland T.L. · Structure no. 012600540013800

Built
1963
62 years old, rebuilt 1992
Condition
Fair
inspected March 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
133 ft
3 main spans
Daily traffic
10,870
2023 count
Owner
State
State Highway Agency

About this bridge

I-93 NB over NH175A is a steel continuous stringer/multi-beam or girder carrying I-93 NB over NH175A in Grafton County, New Hampshire. It was built in 1963 and reconstructed in 1992, so it is 62 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 10,870 vehicles a day, roughly 9% of them trucks, projected to reach 16,087 by 2043. The structure is 133 ft (40.4 m) long and 48 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

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CarriesI-93 NB
CrossesNH175A
Location1.0 MI Ashland T.L.
RouteInterstate 93
CountyGrafton County
StateNew Hampshire
Coordinates43.76007, -71.67733
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.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
Approach roadway alignment8: Equal to present desirable criteria
Operating rating61.6 US tons
Inventory rating36.9 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length133 ft (40.4 m)
Longest span58 ft (17.7 m)
Deck width48 ft (14.6 m)
Roadway width44 ft (13.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10,870 (2023)
Projected traffic16,087 by 2043
Trucks9%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed9.9 mi (16 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-93 NB over NH175A built?

It was built in 1963, making it 62 years old in 2025. It was reconstructed in 1992.

What condition is I-93 NB over NH175A 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 March 2023.

How much traffic does I-93 NB over NH175A carry?

About 10,870 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is I-93 NB over NH175A?

The structure is 133 ft (40.4 m) long with a longest span of 58 ft (17.7 m) and a deck 48 ft wide.

Who owns I-93 NB over NH175A?

It is owned by the State Highway Agency.