Structure 6502010002400 · Strafford County, NH

US 4 Nh 16 Tpk SB over Little Bay RD

Carries US 4 Nh 16 Tpk SB over Little Bay RD, Dover-newington T.l..

Overall conditionGood

Set by its lowest-rated component: Substructure at 7 of 9.

How ratings work
Deck8/9 · Very Good
Superstructure8/9 · Very Good
Substructuresets the rating7/9 · Good
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT1,649 FT OVERALL250 FT0ELEVATION · LENGTHS TO SCALE
Deck 8/9Superstructure 8/9Substructure 7/9 · sets the rating

1,649 ft end to end, longest span 275 ft: about 4.6 football fields. 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 multi-beam bridge.

Built20188 years old
Length1648.6 ft502.5 m
Daily traffic33,938counted 2023
Last inspectedJuly 2023every 24 months

Location

StateNew Hampshire
CountyStrafford
LocationDover-newington T.l.
CarriesUS 4 Nh 16 Tpk SB
CrossesLittle Bay RD
Coordinates43.11809, -70.82589

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length1648.6 ft (502.5 m)
Max Span274.9 ft (83.8 m)
Deck Width75.1 ft (22.9 m)
Deck Area11507.2 sq m
Main Spans9
Year Built2018

Traffic

Avg Daily Traffic33,938 (2023)
Truck Traffic8%
Lanes On Bridge4
Lanes Under Bridge2

Inspection & Ownership

Last InspectionJuly 2023
Inspection FrequencyEvery 24 months
OwnerState Toll Authority
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number006502010002400

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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