Structure 8700780011600 · Grafton County, NH

I-93 NB over Coal Hill RD Gale River

Carries I-93 NB over Coal Hill RD Gale River, 1.9mi Sugarhill Tl.

Overall conditionFair

Set by its lowest-rated component: Deck at 6 of 9.

How ratings work
Decksets the rating6/9 · Satisfactory
Superstructure7/9 · Good
Substructure7/9 · Good
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT191 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 7/9Substructure 7/9

191 ft end to end, longest span 69 ft: about 3 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 multi-beam bridge.

Built1973rebuilt 1991
Length190.9 ft58.2 m
Daily traffic2,612counted 2023
Last inspectedAugust 2023every 24 months

Location

StateNew Hampshire
CountyGrafton
Location1.9mi Sugarhill Tl
CarriesI-93 NB
CrossesCoal Hill RD Gale River
Coordinates44.21839, -71.72876

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length190.9 ft (58.2 m)
Max Span68.9 ft (21 m)
Deck Width65.6 ft (20 m)
Deck Area1,164 sq m
Main Spans3
Year Built1973 (reconstructed 1991)

Traffic

Avg Daily Traffic2,612 (2023)
Truck Traffic9%
Lanes On Bridge2
Lanes Under Bridge2

Inspection & Ownership

Last InspectionAugust 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number008700780011600

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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