US Bridges

Lower Ridge Road over Academy Brook

Good

Merrimack County, New Hampshire · 0.8 MI FR Nh 106 · Structure no. 015501470012500

Built
2023
2 years old
Condition
Good
inspected September 2023
Type
Slab
Prestressed Concrete
Length
40 ft
1 main span
Daily traffic
96
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Lower Ridge Road over Academy Brook is a prestressed concrete slab carrying Lower Ridge Road over Academy Brook in Merrimack County, New Hampshire. It was built in 2023, so it is 2 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 9 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 96 vehicles a day, roughly 4% of them trucks, projected to reach 142 by 2043. The structure is 40 ft (12.2 m) long and 26 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

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CarriesLower Ridge Road
CrossesAcademy Brook
Location0.8 MI FR Nh 106
CountyMerrimack County
StateNew Hampshire
Coordinates43.34863, -71.45569
Functional classRural Local

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck9 ExcellentNo problems noted.
Superstructure9 ExcellentNo problems noted.
Substructure9 ExcellentNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation9: Superior to present desirable criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating70.1 US tons
Inventory rating54.2 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans1
Design loadHL 93
Structure length40 ft (12.2 m)
Longest span37 ft (11.3 m)
Deck width26 ft (7.9 m)
Roadway width24 ft (7.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic96 (2023)
Projected traffic142 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.1 mi (13 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCity or Municipal Highway Agency
Maintained byCity or Municipal 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 Lower Ridge Road over Academy Brook built?

It was built in 2023, making it 2 years old in 2025.

What condition is Lower Ridge Road over Academy 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 September 2023.

How much traffic does Lower Ridge Road over Academy Brook carry?

About 96 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Lower Ridge Road over Academy Brook?

The structure is 40 ft (12.2 m) long with a longest span of 37 ft (11.3 m) and a deck 26 ft wide.

Who owns Lower Ridge Road over Academy Brook?

It is owned by the City or Municipal Highway Agency.