US Bridges

I-93 Parkway over Walker Brook

Fair

Grafton County, New Hampshire · 7.3 MI N Woodstock T.L. · Structure no. 014800920010900

Built
1985
40 years old
Condition
Fair
inspected May 2023
Type
Culvert
Concrete Continuous
Length
31 ft
2 main spans
Daily traffic
11,599
2023 count
Owner
State
State Highway Agency

About this bridge

I-93 Parkway over Walker Brook is a concrete continuous culvert carrying I-93 Parkway over Walker Brook in Grafton County, New Hampshire. It was built in 1985, so it is 40 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 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 11,599 vehicles a day, roughly 9% of them trucks, projected to reach 17,166 by 2043. The structure is 31 ft (9.3 m) long and 94 ft wide. If it were closed, the detour would be 29.8 mi (48 km).

Location

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CarriesI-93 Parkway
CrossesWalker Brook
Location7.3 MI N Woodstock T.L.
RouteInterstate 93
CountyGrafton County
StateNew Hampshire
Coordinates44.13953, -71.68445
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.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
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 length31 ft (9.3 m)
Longest span15 ft (4.5 m)
Deck width94 ft (28.5 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11,599 (2023)
Projected traffic17,166 by 2043
Trucks9%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed29.8 mi (48 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 Parkway over Walker Brook built?

It was built in 1985, making it 40 years old in 2025.

What condition is I-93 Parkway over Walker 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 Parkway over Walker Brook carry?

About 11,599 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is I-93 Parkway over Walker Brook?

The structure is 31 ft (9.3 m) long with a longest span of 15 ft (4.5 m) and a deck 94 ft wide.

Who owns I-93 Parkway over Walker Brook?

It is owned by the State Highway Agency.