US Bridges

I-93 NB over Eastman Brook

Good

Grafton County, New Hampshire · 2.51 MI Thornton Tl · Structure no. 028402040007900

Built
1972
53 years old
Condition
Good
inspected April 2023
Type
Culvert
Concrete Continuous
Length
40 ft
2 main spans
Daily traffic
7,017
2023 count
Owner
State
State Highway Agency

About this bridge

I-93 NB over Eastman Brook is a concrete continuous culvert carrying I-93 NB over Eastman Brook in Grafton County, New Hampshire. It was built in 1972, so it is 53 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 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 7,017 vehicles a day, roughly 10% of them trucks, projected to reach 10,385 by 2043. The structure is 40 ft (12.2 m) long and 87 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-93 NB
CrossesEastman Brook
Location2.51 MI Thornton Tl
RouteInterstate 93
CountyGrafton County
StateNew Hampshire
Coordinates43.96933, -71.67504
Functional classRural 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
Channel and channel protection7 GoodSome minor problems.
Culvert7 GoodSome minor problems.
Last inspectionApril 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating99 US tons
Inventory rating63.9 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadHS 20 + Mod
Structure length40 ft (12.2 m)
Longest span8 ft (2.4 m)
Deck width87 ft (26.5 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,017 (2023)
Projected traffic10,385 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 Eastman Brook built?

It was built in 1972, making it 53 years old in 2025.

What condition is I-93 NB over Eastman Brook 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 April 2023.

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

About 7,017 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is I-93 NB over Eastman Brook?

The structure is 40 ft (12.2 m) long with a longest span of 8 ft (2.4 m) and a deck 87 ft wide.

Who owns I-93 NB over Eastman Brook?

It is owned by the State Highway Agency.