Structure 14400520009900 · Grafton County, NH

I-89 SB over Nh 12a

Carries I-89 SB over Nh 12a, 0.5 Mi From Vt S.l..

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
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT158 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 8/9Superstructure 8/9Substructure 8/9

158 ft end to end: about 2 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.

Built201214 years old
Length158.1 ft48.2 m
Daily traffic18,618counted 2023
Last inspectedJune 2023every 24 months

Location

StateNew Hampshire
CountyGrafton
Location0.5 Mi From Vt S.l.
CarriesI-89 SB
CrossesNh 12a
Coordinates43.63148, -72.32011

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length158.1 ft (48.2 m)
Max Span151.2 ft (46.1 m)
Deck Width58.1 ft (17.7 m)
Deck Area853.1 sq m
Main Spans1
Year Built2012

Traffic

Avg Daily Traffic18,618 (2023)
Truck Traffic9%
Lanes On Bridge3
Lanes Under Bridge7

Inspection & Ownership

Last InspectionJune 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure Number014400520009900

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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