US Bridges

US 4 over Nhrr(abd)

Fair

Merrimack County, New Hampshire · 2.4 MI from Wilmot Tl · Structure no. 005801780009100

Built
1937
88 years old, rebuilt 1986
Condition
Fair
inspected May 2024
Type
Girder and Floorbeam System
Steel
Length
104 ft
1 main span
Daily traffic
2,503
2023 count
Owner
State
State Highway Agency

About this bridge

US 4 over Nhrr(abd) is a steel girder and floorbeam system carrying US 4 over Nhrr(abd) in Merrimack County, New Hampshire. It was built in 1937 and reconstructed in 1986, so it is 88 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 5 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 2,503 vehicles a day, roughly 4% of them trucks, projected to reach 3,704 by 2043. The structure is 104 ft (31.7 m) long and 31 ft wide. If it were closed, the detour would be 24.2 mi (39 km).

Location

Open in Google Maps
CarriesUS 4
CrossesNhrr(abd)
Location2.4 MI from Wilmot Tl
RouteU.S. Route 4
CountyMerrimack County
StateNew Hampshire
Coordinates43.50365, -71.87672
Functional classRural Major Collector

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating45 US tons
Inventory rating27 US tons

Structure

Structure typeGirder and Floorbeam System
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length104 ft (31.7 m)
Longest span100 ft (30.5 m)
Deck width31 ft (9.3 m)
Roadway width29 ft (8.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,503 (2023)
Projected traffic3,704 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesPedestrian / bicycle
Detour if closed24.2 mi (39 km)
TollOn a free road
National Highway SystemNo

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)
NavigationNot applicable (no waterway)

Frequently asked questions

When was US 4 over Nhrr(abd) built?

It was built in 1937, making it 88 years old in 2025. It was reconstructed in 1986.

What condition is US 4 over Nhrr(abd) 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 2024.

How much traffic does US 4 over Nhrr(abd) carry?

About 2,503 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is US 4 over Nhrr(abd)?

The structure is 104 ft (31.7 m) long with a longest span of 100 ft (30.5 m) and a deck 31 ft wide.

Who owns US 4 over Nhrr(abd)?

It is owned by the State Highway Agency.