US Bridges

NH106 over Shaker Brook

Fair

Merrimack County, New Hampshire · 4.0 MI N Concord Tl · Structure no. 015501000011400

Built
1951
74 years old
Condition
Fair
inspected April 2024
Type
Culvert
Concrete Continuous
Length
31 ft
2 main spans
Daily traffic
13,249
2023 count
Owner
State
State Highway Agency

About this bridge

NH106 over Shaker Brook is a concrete continuous culvert carrying NH106 over Shaker Brook in Merrimack County, New Hampshire. It was built in 1951, so it is 74 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 13,249 vehicles a day, roughly 4% of them trucks, projected to reach 19,608 by 2043. The structure is 31 ft (9.4 m) long. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesNH106
CrossesShaker Brook
Location4.0 MI N Concord Tl
RouteState Highway 106
CountyMerrimack County
StateNew Hampshire
Coordinates43.31708, -71.47697
Functional classRural Principal Arterial - Other

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 inspectionApril 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating58.5 US tons
Inventory rating35.1 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadH 20
Structure length31 ft (9.4 m)
Longest span15 ft (4.6 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,249 (2023)
Projected traffic19,608 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
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 NH106 over Shaker Brook built?

It was built in 1951, making it 74 years old in 2025.

What condition is NH106 over Shaker 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 April 2024.

How much traffic does NH106 over Shaker Brook carry?

About 13,249 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is NH106 over Shaker Brook?

The structure is 31 ft (9.4 m) long with a longest span of 15 ft (4.6 m).

Who owns NH106 over Shaker Brook?

It is owned by the State Highway Agency.