Structure 5801560010300 · Merrimack County, NH

US 4 over Nhrr(abd)

Carries US 4 over Nhrr(abd), 3.7 Mi From Wilmot Tl.

Overall conditionGood

Set by its lowest-rated component: Deck and Superstructure and Substructure at 9 of 9.

How ratings work
Decksets the rating9/9 · Excellent
Superstructuresets the rating9/9 · Excellent
Substructuresets the rating9/9 · Excellent
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT75 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 9/9Superstructure 9/9Substructure 9/9

75 ft end to end. Lengths and the car on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a multi-beam bridge.

Built20233 years old
Length75.1 ft22.9 m
Daily traffic2,503counted 2023
Last inspectedMay 2024every 24 months

Location

StateNew Hampshire
CountyMerrimack
Location3.7 Mi From Wilmot Tl
CarriesUS 4
CrossesNhrr(abd)
Coordinates43.51948, -71.86418

Physical Characteristics

MaterialConcrete
DesignStringer/Multi-beam
Total Length75.1 ft (22.9 m)
Max Span60.0 ft (18.3 m)
Deck Width38.1 ft (11.6 m)
Deck Area265.6 sq m
Main Spans1
Year Built2023

Traffic

Avg Daily Traffic2,503 (2023)
Lanes On Bridge2

Inspection & Ownership

Last InspectionMay 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number005801560010300

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.

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