Structure 2701350016200 · Merrimack County, NH

I-89(RAMP D) over Turkey River

Carries I-89(RAMP D) over Turkey River, Bow Interchange.

Overall conditionGood

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

How ratings work
Decksets the rating7/9 · Good
Superstructuresets the rating7/9 · Good
Substructuresets the rating7/9 · Good
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT75 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 7/9Substructure 7/9

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.

Built198739 years old
Length75.1 ft22.9 m
Daily traffic8,925counted 2023
Last inspectedApril 2024every 24 months

Location

StateNew Hampshire
CountyMerrimack
LocationBow Interchange
CarriesI-89(RAMP D)
CrossesTurkey River
Coordinates43.17036, -71.53159

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length75.1 ft (22.9 m)
Max Span69.9 ft (21.3 m)
Deck Width34.1 ft (10.4 m)
Deck Area238.2 sq m
Main Spans1
Year Built1987

Traffic

Avg Daily Traffic8,925 (2023)
Truck Traffic6%
Lanes On Bridge1

Inspection & Ownership

Last InspectionApril 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number002701350016200

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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