Structure 18501030012400 · Rockingham County, NH

US 4 Nh 16 Sp Tpk over Shawayttuck

Carries US 4 Nh 16 Sp Tpk over Shawayttuck, 2.5 Mi From Portsmouth T.

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
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT48 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 8/9Superstructure 8/9Substructure 7/9 · sets the rating

48 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 rigid-frame bridge.

Built1983rebuilt 2021
Length47.9 ft14.6 m
Daily traffic68,236counted 2023
Last inspectedApril 2023every 24 months

Location

StateNew Hampshire
CountyRockingham
Location2.5 Mi From Portsmouth T
CarriesUS 4 Nh 16 Sp Tpk
CrossesShawayttuck
Coordinates43.11546, -70.82268

Physical Characteristics

MaterialConcrete
DesignFrame
Total Length47.9 ft (14.6 m)
Max Span42.0 ft (12.8 m)
Deck Width167.3 ft (51 m)
Deck Area744.6 sq m
Main Spans1
Year Built1983 (reconstructed 2021)

Traffic

Avg Daily Traffic68,236 (2023)
Truck Traffic8%
Lanes On Bridge4
Lanes Under Bridge2

Inspection & Ownership

Last InspectionApril 2023
Inspection FrequencyEvery 24 months
OwnerState Toll Authority
Historical SignificanceBridge is possibly eligible (requires evaluation)
Scour CriticalNot applicable
Structure Number018501030012400

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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