US Bridges

I-93 NB over Hubbard Brook

Fair

Grafton County, New Hampshire · 1.3 MI S Woodstock Tl · Structure no. 025401530007400

Built
1970
55 years old
Condition
Fair
inspected May 2023
Type
Culvert
Concrete Continuous
Length
38 ft
2 main spans
Daily traffic
7,102
2023 count
Owner
State
State Highway Agency

About this bridge

I-93 NB over Hubbard Brook is a concrete continuous culvert carrying I-93 NB over Hubbard Brook in Grafton County, New Hampshire. It was built in 1970, so it is 55 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 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 7,102 vehicles a day, roughly 10% of them trucks, projected to reach 10,510 by 2043. The structure is 38 ft (11.6 m) long and 149 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-93 NB
CrossesHubbard Brook
Location1.3 MI S Woodstock Tl
RouteInterstate 93
CountyGrafton County
StateNew Hampshire
Coordinates43.93308, -71.68689
Functional classRural 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
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating99 US tons
Inventory rating99 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadHS 20 + Mod
Structure length38 ft (11.6 m)
Longest span18 ft (5.5 m)
Deck width149 ft (45.5 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,102 (2023)
Projected traffic10,510 by 2043
Trucks10%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesWaterway
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)
NavigationNo navigation control on waterway

Frequently asked questions

When was I-93 NB over Hubbard Brook built?

It was built in 1970, making it 55 years old in 2025.

What condition is I-93 NB over Hubbard Brook 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 May 2023.

How much traffic does I-93 NB over Hubbard Brook carry?

About 7,102 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is I-93 NB over Hubbard Brook?

The structure is 38 ft (11.6 m) long with a longest span of 18 ft (5.5 m) and a deck 149 ft wide.

Who owns I-93 NB over Hubbard Brook?

It is owned by the State Highway Agency.