Structure 400680005500 · Merrimack County, NH

US 3 over Suncook River Buck ST

Carries US 3 over Suncook River Buck ST, Pembroke-allenstown Tl.

Overall conditionGood

Set by its lowest-rated component: Deck and Superstructure and Substructure at 8 of 9.

How ratings work
Decksets the rating8/9 · Very Good
Superstructuresets the rating8/9 · Very Good
Substructuresets the rating8/9 · Very Good
Channelnot part of overall9/9 · Excellent
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT440 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 8/9Superstructure 8/9Substructure 8/9

440 ft end to end: about 6 semi-trucks nose to tail. Lengths and the semi-truck 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 deck truss.

Built200719 years old
Length440.0 ft134.1 m
Daily traffic9,285counted 2023
Last inspectedApril 2023every 24 months

Location

StateNew Hampshire
CountyMerrimack
LocationPembroke-allenstown Tl
CarriesUS 3
CrossesSuncook River Buck ST
Coordinates43.13070, -71.44620

Physical Characteristics

MaterialSteel
DesignTruss - Deck
Total Length440.0 ft (134.1 m)
Max Span168.0 ft (51.2 m)
Deck Width47.2 ft (14.4 m)
Deck Area1931.0 sq m
Main Spans1
Year Built2007

Traffic

Avg Daily Traffic9,285 (2023)
Truck Traffic7%
Lanes On Bridge2
Lanes Under Bridge2

Inspection & Ownership

Last InspectionApril 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number000400680005500

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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