US Bridges

Loudon Ridge Road over Academy Brook

Good

Merrimack County, New Hampshire · 0.4 MI FR Lowerridge RD · Structure no. 015501990011300

Built
2023
2 years old
Condition
Good
inspected September 2023
Type
Slab
Concrete
Length
40 ft
1 main span
Daily traffic
260
2023 count
Owner
City
City or Municipal Highway Agency

About this bridge

Loudon Ridge Road over Academy Brook is a concrete slab carrying Loudon 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 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 260 vehicles a day, roughly 4% of them trucks, projected to reach 384 by 2043. The structure is 40 ft (12.2 m) long and 27 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesLoudon Ridge Road
CrossesAcademy Brook
Location0.4 MI FR Lowerridge RD
CountyMerrimack County
StateNew Hampshire
Coordinates43.37454, -71.41743
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
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating70 US tons
Inventory rating54.2 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, precast panels
Main spans1
Design loadHL 93
Structure length40 ft (12.2 m)
Longest span34 ft (10.4 m)
Deck width27 ft (8.1 m)
Roadway width23 ft (7.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic260 (2023)
Projected traffic384 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 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 Loudon Ridge Road over Academy Brook built?

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

What condition is Loudon 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 Loudon Ridge Road over Academy Brook carry?

About 260 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is Loudon Ridge Road over Academy Brook?

The structure is 40 ft (12.2 m) long with a longest span of 34 ft (10.4 m) and a deck 27 ft wide.

Who owns Loudon Ridge Road over Academy Brook?

It is owned by the City or Municipal Highway Agency.